Oracle® Database JDBC Developer's Guide and Reference 10g Release 2 (10.2) Part Number B14355-02 |
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Oracle provides Java classes and interfaces that extend the Java Database Connectivity (JDBC) standard implementation, enabling you to access and manipulate Oracle data types and use Oracle performance extensions. Compared to standard JDBC, the Oracle extensions offer greater flexibility in manipulating the data. This chapter provides an overview of the classes and interfaces provided by Oracle that extend the JDBC standard implementation. It also describes some of the key support features of the extensions.
This chapter contains the following sections:
Additional Oracle Type Extensions
Note:
This chapter focuses on type extensions, as opposed to performance extensions, which are discussed in detail in Chapter 25, "Performance Extensions".Beyond standard features, Oracle JDBC drivers provide Oracle-specific type extensions and performance extensions. These extensions are provided through the following Java packages:
oracle.sql
Provides classes that represent SQL data in Oracle format
oracle.jdbc
Provides interfaces to support database access and updates in Oracle type formats
See Also:
"Oracle JDBC Packages"The Oracle extensions to JDBC include a number of features that enhance your ability to work with Oracle databases. Among these are support for:
Oracle data types
Oracle objects
Specific schema naming
DML returning
Accessing PL/SQL index-by tables.
This section covers the following topics:
A key feature of the Oracle JDBC extensions is the type support in the oracle.sql
package. This package includes classes that map to all the Oracle SQL data types, acting as wrappers for raw SQL data. This functionality provides two significant advantages in manipulating SQL data:
Accessing data directly in SQL format is sometimes more efficient than first converting it to Java format.
Performing mathematical manipulations of the data directly in SQL format avoids the loss of precision that can occur in converting between SQL and Java formats.
Once manipulations are complete and it is time to output the information, each of the oracle.sql.*
date type support classes has all the necessary methods to convert data to appropriate Java formats.
Oracle JDBC supports the use of structured objects in the database, where an object data type is a user-defined type with nested attributes. For example, a user application could define an Employee
object type, where each Employee
object has a firstname
attribute (character string), a lastname
attribute (character string), and an employeenumber
attribute (integer).
JDBC implementation of Oracle supports Oracle object data types. When you work with Oracle object data types in a Java application, you must consider the following:
How to map between Oracle object data types and Java classes
How to store Oracle object attributes in corresponding Java objects
How to convert attribute data between SQL and Java formats
How to access data
Oracle objects can be mapped either to the weak java.sql.Struct
or oracle.sql.STRUCT
types or to strongly typed customized classes. These strong types are referred to as custom Java classes, which must implement either the standard java.sql.SQLData
interface or the Oracle extension oracle.sql.ORAData
interface. Each interface specifies methods to convert data between SQL and Java.
Note:
TheORAData
interface has replaced the CustomDatum
interface. While the latter interface is deprecated, it is still supported for backward compatibility.Oracle recommends the use of the Oracle JPublisher utility to create custom Java classes to correspond to your Oracle objects. Oracle JPublisher performs this task seamlessly with command-line options and can generate either SQLData
or ORAData
implementations.
For SQLData
implementations, a type map defines the correspondence between Oracle object data types and Java classes. Type maps are objects that specify which Java class corresponds to each Oracle object data type. Oracle JDBC uses these type maps to determine which Java class to instantiate and populate when it retrieves Oracle object data from a result set.
Note:
Oracle recommends using theORAData
interface, instead of the SQLData
interface, in situations where portability is not a concern. ORAData
works more easily and flexibly in conjunction with other features of the Oracle Java platform offerings.JPublisher automatically defines get
XXX
methods of the custom Java classes, which retrieve data into your Java application. For more information on the JPublisher utility.
Oracle object data type classes have the ability to accept and return fully qualified schema names. A fully qualified schema name has this syntax:
{[schema_name].}[sql_type_name]
Where schema_name
is the name of the schema and sql_type_name
is the SQL type name of the object. schema_name
and sql_type_name
are separated by a period (.
).
To specify an object type in JDBC, use its fully qualified name. It is not necessary to enter a schema name if the type name is in current naming space, that is, the current schema. Schema naming follows these rules:
Both the schema name and the type name may or may not be quoted. However, if the SQL type name has a period in it, such as CORPORATE.EMPLOYEE
, the type name must be quoted.
The JDBC driver looks for the first unquoted period in the object name and uses the string before the period as the schema name and the string following the period as the type name. If no period is found, then the JDBC driver takes the current schema as default. That is, you can specify only the type name, without indicating a schema, instead of specifying the fully qualified name if the object type name belongs to the current schema. This also explains why you must quote the type name if the type name has a dot in it.
For example, assume that user Scott creates a type called person.address
and then wants to use it in his session. Scott may want to skip the schema name and pass in person.address
to the JDBC driver. In this case, if person.address
is not quoted, then the period will be detected and the JDBC driver will mistakenly interpret person
as the schema name and address
as the type name.
JDBC passes the object type name string to the database unchanged. That is, the JDBC driver will not change the character case even if it is quoted.
For example, if Scott.PersonType
is passed to the JDBC driver as an object type name, then the JDBC driver will pass the string to the database unchanged. As another example, if there is white space between characters in the type name string, then the JDBC driver will not remove the white space.
Oracle Database supports the use of the RETURNING
clause with data manipulation language (DML) statements. This enables you to combine two SQL statements into one. Both the Oracle JDBC Oracle Call Interface (OCI) driver and the Oracle JDBC Thin driver support DML returning. DML returning provides richer functionality compared to retrieval of auto-generated keys. It can be used to retrieve not only auto-generated keys, but also other columns or values that the application may use.
Note:
The server-side internal driver does not support DML returning and retrieval of auto-generated keys.See Also:
"DML Returning"The Oracle JDBC drivers enable JDBC applications to make PL/SQL calls with index-by table parameters. The Oracle JDBC drivers support PL/SQL index-by tables of scalar data types
Note:
Index-by tables of PL/SQL records are not supported.See Also:
"Accessing PL/SQL Index-by Tables"This section describes the following Java packages, which support the Oracle JDBC extensions:
The oracle.sql
package supports direct access to data in SQL format. This package consists primarily of classes that provide Java mappings to SQL data types and their support classes.
Essentially, the classes act as Java wrappers for SQL data. The characters are converted to Java chars and, then, to bytes in the UCS2 character set.
Each of the oracle.sql.*
data type classes extends oracle.sql.Datum
, a superclass that encapsulates functionality common to all the data types. Some of the classes are for JDBC 2.0-compliant data types. These classes, as Table 5-1 indicates, implement standard JDBC 2.0 interfaces in the java.sql
package, as well as extending the oracle.sql.Datum
class.
Classes of the oracle.sql Package
Table 5-1 lists the oracle.sql
data type classes and their corresponding Oracle SQL types.
Table 5-1 Oracle Data Type Classes
Java Class | Oracle SQL Types and Interfaces Implemented |
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SQL |
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Note:
TheLONG
and LONG
RAW
SQL types and REF
CURSOR
type category have no oracle.sql.*
classes. Use standard JDBC functionality for these types. For example, retrieve LONG
or LONG
RAW
data as input streams using the standard JDBC result set and callable statement methods getBinaryStream
and getCharacterStream
. Use the getCursor
method for REF
CURSOR
types.In addition to the data type classes, the oracle.sql
package includes the following support classes and interfaces, primarily for use with objects and collections:
oracle.sql.ArrayDescriptor
This class is used in constructing oracle.sql.ARRAY
objects. It describes the SQL type of the array.
oracle.sql.StructDescriptor
This class is used in constructing oracle.sql.STRUCT
objects, which you can use as a default mapping to Oracle objects in the database.
oracle.sql.ORAData
and oracle.sql.ORADataFactory
These interfaces are used in Java classes implementing the Oracle ORAData
scenario of Oracle object support.
oracle.sql.OpaqueDescriptor
This class is used to obtain the meta data for an instance of the oracle.sql.OPAQUE
class.
General oracle.sql.* Data Type Support
Each of the Oracle data type classes provides, among other things, the following:
One or more constructors, typically with a constructor that uses raw bytes as input and a constructor that takes a Java type as input
Data storage as Java byte arrays for SQL data
A getBytes()
method, which returns the SQL data as a byte array
A toJdbc()
method that converts the data into an object of a corresponding Java class as defined in the JDBC specification
The JDBC driver does not convert Oracle-specific data types that are not part of the JDBC specification, such as ROWID
. The driver returns the object in the corresponding oracle.sql.*
format. For example, it returns an Oracle ROWID as an oracle.sql.ROWID
.
Appropriate xxx
Value
methods to convert SQL data to Java type. For example, stringValue
, intValue
, booleanValue
, dateValue
, and bigDecimalValue
Additional conversion methods, get
XXX
and set
XXX
, as appropriate, for the functionality of the data type, such as methods in the large object (LOB) classes that get the data as a stream and methods in the REF
class that get and set object data through the object reference
Overview of Class oracle.sql.STRUCT
For any given Oracle object type, it is usually desirable to define a custom mapping between SQL and Java. For example, if you use a SQLData
custom Java class, then the mapping must be defined in a type map.
If you choose not to define a mapping, however, then data from the object type will be materialized in Java in an instance of the oracle.sql.STRUCT
class.
The STRUCT
class implements the standard JDBC 2.0 java.sql.Struct
interface and extends the oracle.sql.Datum
class.
A STRUCT
object is a Java representation of the raw bytes of an Oracle object. It contains the SQL type name of the Oracle object and an array of oracle.sql.Datum
objects that hold the attribute values in SQL format.
The signature of the constructors for STRUCT
are as follows:
STRUCT(Connection connection, java.sql.StructDescriptor structDescriptor, Object[] attributes) STRUCT(Connection connection, java.sql.StructDescriptor structDescriptor, java.util.Map map)
You can materialize attributes of a STRUCT
object as oracle.sql.Datum[]
objects, if you use the getOracleAttributes
method, or as java.lang.Object[]
objects, if you use the getAttributes
method. Materializing the attributes as oracle.sql.*
objects gives you the following advantages of the oracle.sql.*
format:
Materializing oracle.sql.STRUCT
data in oracle.sql.*
format completely preserves data by maintaining it in SQL format. No translation is performed. This is useful if you want to access data but not necessarily display it.
It allows complete flexibility in how your Java application unpacks data.
Notes:
Elements of the array, although of the generic Datum
type, actually contain data associated with the relevant oracle.sql.*
type appropriate for the given attribute. You can cast the element to the appropriate oracle.sql.*
type as desired. For example, a CHAR
data attribute within the STRUCT
is materialized as oracle.sql.Datum
. To use it as CHAR
data, you must cast it to oracle.sql.CHAR
.
Nested objects in the values array of a STRUCT
object are materialized by the JDBC driver as instances of STRUCT
.
In some cases, you may want to manually create a STRUCT
object and pass it to a prepared statement or callable statement. To do this, you must also create a StructDescriptor
object.
Overview of Class oracle.sql.REF
The oracle.sql.REF
class is the generic class that supports Oracle object references. This class, as with all oracle.sql.*
data type classes, is a subclass of the oracle.sql.Datum
class. It implements the standard JDBC 2.0 java.sql.Ref
interface.
The REF
class has methods to retrieve and pass object references. However, selecting an object reference retrieves only a pointer to an object. This does not materialize the object itself. But the REF
class also includes methods to retrieve and pass the object data.
You cannot create REF
objects in your JDBC application. You can only retrieve existing REF
objects from the database.
See Also:
Chapter 17, "Using Oracle Object References".Overview of Class oracle.sql.ARRAY
The oracle.sql.ARRAY
class supports Oracle collections, either VARRAYs or nested tables. If you select either a VARRAY or a nested table from the database, then the JDBC driver materializes it as an object of the ARRAY
class. The structure of the data is equivalent in either case. The oracle.sql.ARRAY
class extends oracle.sql.Datum
and implements the standard JDBC 2.0 java.sql.Array
interface.
You can use the setARRAY
method of the OraclePreparedStatement
or OracleCallableStatement
class to pass an ARRAY
as an input parameter to a prepared statement. Similarly, you might want to manually create an ARRAY
object to pass it to a prepared statement or callable statement, perhaps to insert into the database. This involves the use of ArrayDescriptor
objects.
See Also:
"Overview of Collection Functionality"Overview of Classes oracle.sql.BLOB, oracle.sql.CLOB, oracle.sql.BFILE
Binary large objects (BLOBs), character large objects (CLOBs), and binary files (BFILEs) are for data items that are too large to store directly in a database table. Instead, the database table stores a locator that points to the location of the actual data.
The oracle.sql
package supports these data types in several ways:
BLOBs point to large unstructured binary data items and are supported by the oracle.sql.BLOB
class.
CLOBs point to large character data items and are supported by the oracle.sql.CLOB
class.
BFILEs point to the content of external files (operating system files) and are supported by the oracle.sql.BFILE
class.
You can select a BLOB, CLOB, or BFILE locator from the database using a standard SELECT
statement. However, you receive only the locator, and not the data. Additional steps are necessary to retrieve the data.
See Also:
Chapter 16, "Working with LOBs and BFILEs".Classes oracle.sql.DATE, oracle.sql.NUMBER, and oracle.sql.RAW
These classes map to primitive SQL data types, which are a part of standard JDBC, and supply conversions to and from the corresponding JDBC Java types.
Because Java Double
and Float
NaN
values do not have an equivalent Oracle NUMBER
representation, a NullPointerException
is thrown whenever a Double.NaN
value or a Float.NaN
value is converted into an Oracle NUMBER
using oracle.sql.NUMBER
, For instance, the following code throws a NullPointerException
:
oracle.sql.NUMBER n = new oracle.sql.NUMBER(Double.NaN); System.out.println(n.doubleValue()); // throws NullPointerException
Classes oracle.sql.TIMESTAMP, oracle.sql.TIMESTAMPTZ, and oracle.sql.TIMESTAMPLTZ
The JDBC drivers support the following date/time data types:
TIMESTAMP
(TIMESTAMP
)
TIMESTAMP WITH TIME ZONE
(TIMESTAMPTZ
)
TIMESTAMP WITH LOCAL TIME ZONE
(TIMESTAMPLTZ
)
The JDBC drivers allow conversions between DATE
and date/time data types. For example, you can access a TIMESTAMP WITH TIME ZONE
column as a DATE
value.
The JDBC drivers support the most popular time zone names used in the industry as well as most of the time zone names defined in the JDK from Sun Microsystems. Time zones are specified by using the java.util.Calendar
class.
Note:
Do not useTimeZone.getTimeZone
to create time zone objects. The Oracle time zone data types support more time zone names than does the JDK.The following code shows how the TimeZone
and Calendar
objects are created for US_PACIFIC
, which is a time zone name not defined in the JDK:
TimeZone tz = TimeZone.getDefault(); tz.setID("US_PACIFIC"); GregorianCalendar gcal = new GregorianCalendar(tz);
The following Java classes represent the SQL date/time types:
oracle.sql.TIMESTAMP
oracle.sql.TIMESTAMPTZ
oracle.sql.TIMESTAMPLTZ
Before accessing TIMESTAMP WITH LOCAL TIME ZONE
data, call the OracleConnection.setSessionTimeZone(String regionName)
method to set the session time zone. When this method is called, the JDBC driver sets the session time zone of the connection and saves the session time zone so that any TIMESTAMP WITH LOCAL TIME ZONE
data accessed through JDBC can be adjusted using the session time zone.
Overview of Class oracle.sql.ROWID
This class supports Oracle ROWIDs, which are unique identifiers for rows in database tables. You can select a ROWID as you would select any column of data from the table. Note, however, that you cannot manually update ROWIDs. The Oracle Database updates them automatically as appropriate.
The oracle.sql.ROWID
class does not implement any noteworthy functionality beyond what is in the oracle.sql.Datum
superclass. However, ROWID
does provide a stringValue
method that overrides the stringValue
method in the oracle.sql.Datum
class and returns the hexadecimal representation of the ROWID
bytes.
See Also:
"Oracle ROWID Type"Class oracle.sql.OPAQUE
The oracle.sql.OPAQUE
class gives you the name and characteristics of the OPAQUE type and any attributes. OPAQUE type provides access only to the uninterrupted bytes of the instance.
Note:
There is minimal support for OPAQUE type.The following are the methods of the oracle.sql.OPAQUE
class:
getBytesValue
Returns a byte
array that represents the value of the OPAQUE
object, in the format used in the database.
isConvertibleTo(Class jClass)
Determines if a Datum
object can be converted to a particular class, where Class
is any class and jClass
is the class to convert. true
is returned if conversion to jClass
is permitted and, false
is returned if conversion to jClass
is not permitted.
getDescriptor
Returns the OpaqueDescriptor
object that contains the type information.
getJavaSqlConnection
Returns the connection associated with the receiver. Because methods that use the oracle.jdbc.driver
package are deprecated, the getConnection
method has been deprecated in favor of the getJavaSqlConnection
method.
getSQLTypeName
Implements the java.sql.Struct
interface function and retrieves the SQL type name of the SQL structured type that this Struct
object represents. This method returns the fully-qualified type name of the SQL structured type which this STRUCT
object represents.
getValue
Returns a Java object that represents the value.
toJdbc
Returns the JDBC representation of the Datum
object.
The interfaces of the oracle.jdbc
package define the Oracle extensions to the interfaces in java.sql
. These extensions provide access to Oracle SQL-format data and other Oracle-specific functionality, including Oracle performance enhancements.
See Also:
"The oracle.jdbc Package"Oracle character data types include the SQL CHAR and NCHAR data types. The following sections describe how these data types can be accessed using the oracle.sql.*
classes:
The SQL CHAR data types include CHAR
, VARCHAR2
, and CLOB
. These data types let you store character data in the database character set encoding scheme. The character set of the database is established when you create the database.
The SQL NCHAR data types were created for Globalization Support. The SQL NCHAR data types include NCHAR
, NVARCHAR2
, and NCLOB
. These data types allow you to store Unicode data in the database NCHAR character set encoding. The NCHAR character set, which never changes, is established when you create the database.
Note:
Because theUnicodeStream
class is deprecated in favor of the CharacterStream
class, the setUnicodeStream
and getUnicodeStream
methods are not supported for NCHAR data type access. Use the setCharacterStream
method and the getCharacterStream
method if you want to use stream access.The usage of SQL NCHAR data types is similar to that of the SQL CHAR data types. JDBC uses the same classes and methods to access SQL NCHAR data types that are used for the corresponding SQL CHAR data types. Therefore, there are no separate, corresponding classes defined in the oracle.sql
package for SQL NCHAR data types. Similarly, there is no separate, corresponding constant defined in the oracle.jdbc.OracleTypes
class for SQL NCHAR data types. The only difference in usage between the two data types occur in a data bind situation: a JDBC program must call the setFormOfUse
method to specify if the data is bound for a SQL NCHAR data type.
Note:
ThesetFormOfUse
method must be called before the registerOutParameter
method is called in order to avoid unpredictable results.The following code shows how to access SQL NCHAR data:
// // Table TEST has the following columns: // - NUMBER // - NVARCHAR2 // - NCHAR // oracle.jdbc.OraclePreparedStatement pstmt = (oracle.jdbc.OraclePreparedStatement) conn.prepareStatement("insert into TEST values(?, ?, ?)"); // // oracle.jdbc.OraclePreparedStatement.FORM_NCHAR should be used for all NCHAR, // NVARCHAR2 and NCLOB data types. // pstmt.setFormOfUse(2, OraclePreparedStatement.FORM_NCHAR); pstmt.setFormOfUse(3, OraclePreparedStatement.FORM_NCHAR); pstmt.setInt(1, 1); // NUMBER column pstmt.setString(2, myUnicodeString1); // NVARCHAR2 column pstmt.setString(3, myUnicodeString2); // NCHAR column pstmt.execute(); OraclePreparedStatement.FORM_NCHAR
The oracle.sql.CHAR
class is used by Oracle JDBC in handling and converting character data. This class provides the Globalization Support functionality to convert character data. This class has two key attributes: Globalization Support character set and the character data. The Globalization Support character set defines the encoding of the character data. It is a parameter that is always passed when a CHAR
object is constructed. Without the Globalization Support character set information, the data bytes in the CHAR
object are meaningless. The oracle.sql.CHAR
class is used for both SQL CHAR and SQL NCHAR data types.
Note:
In versions of the Oracle JDBC drivers prior to 10g release 1 (10.1), there were performance advantages to usingoracle.SQL.CHAR
. In Oracle Database 10g, there are no longer any such advantages. In fact, optimum performance is achieved using java.lang.String
. All Oracle JDBC drivers handle all character data in the Java UCS2 character set. Using oracle.sql.CHAR
does not prevent conversions between the database character set and UCS2.The only remaining use of oracle.sql.CHAR
is to handle character data in the form of raw bytes encoded in an Oracle Globalization Support character set. All character data retrieved from Oracle Database should be accessed using java.lang.String
. When processing byte data from another source, you can use an oracle.sql.CHAR
to convert the bytes to java.lang.String
.
To convert an oracle.sql.CHAR
, you must provide the data bytes and an oracle.sql.CharacterSet
instance that represents the Globalization Support character set used to encode the data bytes.
The CHAR
objects that are Oracle object attributes are returned in the database character set.
JDBC application code rarely needs to construct CHAR
objects directly, because the JDBC driver automatically creates CHAR objects as needed.
To construct a CHAR
object, you must provide character set information to the CHAR
object by way of an instance of the CharacterSet
class. Each instance of this class represents one of the Globalization Support character sets that Oracle supports. A CharacterSet
instance encapsulates methods and attributes of the character set, mainly involving functionality to convert to or from other character sets.
Constructing an oracle.sql.CHAR Object
Follow these general steps to construct a CHAR
object:
Create a CharacterSet
object by calling the static
CharacterSet.make
method.
This method is a factory for the character set instance. The make
method takes an integer as input, which corresponds to a character set ID that Oracle supports. For example:
int oracleId = CharacterSet.JA16SJIS_CHARSET; // this is character set ID, // 832 ... CharacterSet mycharset = CharacterSet.make(oracleId);
Each character set that Oracle supports has a unique, predefined Oracle ID.
Construct a CHAR
object.
Pass a string, or the bytes that represent the string, to the constructor along with the CharacterSet
object that indicates how to interpret the bytes based on the character set. For example:
String mystring = "teststring"; ... CHAR mychar = new CHAR(teststring, mycharset);
The CHAR
class has multiple constructors, which can take a String
, a byte
array, or an object as input along with the CharacterSet
object. In the case of a String
, the string is converted to the character set indicated by the CharacterSet
object before being placed into the CHAR
object.
Notes:
The CharacterSet
object cannot be null.
The CharacterSet
class is an abstract class, therefore it has no constructor. The only way to create instances is to use the make
method.
The server recognizes the special value CharacterSet.DEFAULT_CHARSET
as the database character set. For the client, this value is not meaningful.
Oracle does not intend or recommend that users extend the CharacterSet
class.
oracle.sql.CHAR Conversion Methods
The CHAR
class provides the following methods for translating character data to strings:
Converts the sequence of characters represented by the CHAR
object to a string, returning a Java String
object. If you enter an invalid OracleID
, then the character set will not be recognized and the getString
method throws a SQLException
.
Identical to the getString
method. But if you enter an invalid OracleID
, then the character set will not be recognized and the toString
method returns a hexadecimal representation of the CHAR
data and does not throw a SQLException
.
Identical to getString
, except a default replacement character replaces characters that have no unicode representation in the CHAR
object character set. This default character varies from character set to character set, but is often a question mark (?
).
The database server and the client, or application running on the client, can use different character sets. When you use the methods of the CHAR
class to transfer data between the server and the client, the JDBC drivers must convert the data from the server character set to the client character set or vice versa. To convert the data, the drivers use Globalization Support.
See Also:
Chapter 21, "Globalization Support"This section covers additional Oracle type extensions. Oracle JDBC drivers support the Oracle-specific BFILE
and ROWID
data types and REF
CURSOR
types, which are not part of the standard JDBC specification. This section describes the ROWID
and REF CURSOR
type extensions. ROWID
is supported as a Java string, and REF
CURSOR
types are supported as JDBC result sets.
This section covers the following topics:
A ROWID is an identification tag unique for each row of an Oracle Database table. The ROWID can be thought of as a virtual column, containing the ID for each row.
The oracle.sql.ROWID
class is supplied as a wrapper for ROWID
SQL data type.
ROWIDs provide functionality similar to the getCursorName
method specified in the java.sql.ResultSet
interface and the setCursorName
method specified in the java.sql.Statement
interface.
If you include the ROWID pseudo-column in a query, then you can retrieve the ROWIDs with the result set getString
method. You can also bind a ROWID to a PreparedStatement
parameter with the setString
method. This enables in-place updation, as in the example that follows.
Note:
Theoracle.sql.ROWID
class replaces oracle.jdbc.driver.ROWID
, which was used in previous releases of Oracle JDBC.Example
The following example shows how to access and manipulate ROWID
data:
Statement stmt = conn.createStatement(); // Query the employee names with "FOR UPDATE" to lock the rows. // Select the ROWID to identify the rows to be updated. ResultSet rset = stmt.executeQuery ("SELECT ename, rowid FROM emp FOR UPDATE"); // Prepare a statement to update the ENAME column at a given ROWID PreparedStatement pstmt = conn.prepareStatement ("UPDATE emp SET ename = ? WHERE rowid = ?"); // Loop through the results of the query while (rset.next ()) { String ename = rset.getString (1); oracle.sql.ROWID rowid = rset.getROWID (2); // Get the ROWID as a String pstmt.setString (1, ename.toLowerCase ()); pstmt.setROWID (2, rowid); // Pass ROWID to the update statement pstmt.executeUpdate (); // Do the update }
A cursor variable holds the memory location of a query work area, rather than the contents of the area. Declaring a cursor variable creates a pointer. In SQL, a pointer has the data type REF
x
, where REF
is short for REFERENCE
and x
represents the entity being referenced. A REF CURSOR
, then, identifies a reference to a cursor variable. Because many cursor variables might exist to point to many work areas, REF
CURSOR
can be thought of as a category or data type specifier that identifies many different types of cursor variables.
Note:
REF CURSOR
instances are not scrollable.To create a cursor variable, begin by identifying a type that belongs to the REF
CURSOR
category. For example:
DECLARE TYPE DeptCursorTyp IS REF CURSOR
Then, create the cursor variable by declaring it to be of the type DeptCursorTyp
:
dept_cv DeptCursorTyp - - declare cursor variable ...
REF
CURSOR
, then, is a category of data types, rather than a particular data type.
Stored procedures can return cursor variables of the REF
CURSOR
category. This output is equivalent to a database cursor or a JDBC result set. A REF CURSOR
essentially encapsulates the results of a query.
In JDBC, a
REF CURSOR
is materialized as a ResultSet
object and can be accessed as follows:
Use a JDBC callable statement to call a stored procedure. It must be a callable statement, as opposed to a prepared statement, because there is an output parameter.
The stored procedure returns a REF CURSOR
.
The Java application casts the callable statement to an Oracle callable statement and uses the getCursor
method of the OracleCallableStatement
class to materialize the REF CURSOR
as a JDBC ResultSet
object.
The result set is processed as requested.
Important:
The cursor associated with aREF CURSOR
is closed whenever the statement object that produced the REF CURSOR
is closed.
Unlike in past releases, the cursor associated with a REF CURSOR
is not closed when the result set object in which the REF CURSOR
was materialized is closed.
Example
This example shows how to access REF CURSOR
data.
import oracle.jdbc.*; ... CallableStatement cstmt; ResultSet cursor; // Use a PL/SQL block to open the cursor cstmt = conn.prepareCall ("begin open ? for select ename from emp; end;"); cstmt.registerOutParameter(1, OracleTypes.CURSOR); cstmt.execute(); cursor = ((OracleCallableStatement)cstmt).getCursor(1); // Use the cursor like a normal ResultSet while (cursor.next ()) {System.out.println (cursor.getString(1));}
In the preceding example:
A CallableStatement
object is created by using the prepareCall
method of the connection class.
The callable statement implements a PL/SQL procedure that returns a REF CURSOR
.
As always, the output parameter of the callable statement must be registered to define its type. Use the type code OracleTypes.CURSOR
for a REF CURSOR
.
The callable statement is run, returning the REF CURSOR
.
The CallableStatement
object is cast to OracleCallableStatement
to use the getCursor
method, which is an Oracle extension to the standard JDBC API, and returns the REF CURSOR
into a ResultSet
object.
The Oracle BINARY_FLOAT
and BINARY_DOUBLE
types are used to store IEEE 574 float and double data. These correspond to the Java float
and double
scalar types with the exception of negative zero and NaN
.
See Also:
Oracle Database SQL Language ReferenceIf you include a BINARY_DOUBLE
column in a query, then the data is retrieved from the database in the binary format. Also, the getDouble
method will return the data in the binary format. In contrast for a NUMBER
type column, the number bits are returned and converted to the Java double
type.
Note:
The Oracle representation for the SQLFLOAT
, DOUBLE PRECISION
, and REAL
types use the Oracle NUMBER
representation. The BINARY_FLOAT
and BINARY_DOUBLE
types can be regarded as proprietary types.A call to the JDBC standard setDouble(int, double)
method of PreparedStatement
converts the Java double
argument to Oracle NUMBER
style bits and send them to the database. In contrast, the setBinaryDouble(int, double)
method of oracle.jdbc.OraclePreparedStatement
converts the data to the internal binary bits and sends them to the database.
You must ensure that the data format used matches the type of the target parameter of PreparedStatement
. This will result in correct data and least use of CPU. If you use setBinaryDouble
for a NUMBER
parameter, then the binary bits are sent to the server and converted to NUMBER
format. The data will be correct, but server CPU load will be increased. If you use setDouble
for a BINARY_DOUBLE
parameter, then the data will first be converted to NUMBER
bits on the client and sent to the server, where it will be converted back to binary format. This will use excess CPU on both client and server and can result in data corruption as well.
The SetFloatAndDoubleUseBinary
connection property when set to true
causes the JDBC standard APIs, setFloat(int, float)
, setDouble(int, double)
, and all the variations, to send internal binary bits instead of NUBMER
bits.
Note:
Although this section largely discusses aboutBINARY_DOUBLE
, the same is true for BINARY_FLOAT
.The interfaces of the oracle.jdbc
package define the Oracle extensions to the interfaces in java.sql
. These extensions provide access to Oracle SQL-format data as described in this chapter. They also provide access to other Oracle-specific functionality, including Oracle performance enhancements.
For the oracle.jdbc
package, Table 5-2 lists key interfaces and classes used for connections, statements, and result sets.
Table 5-2 Key Interfaces and Classes of the oracle.jdbc Package
Name | Interface or Class | Key Functionality |
---|---|---|
|
Class |
Implements |
|
Interface |
Provides methods to return Oracle statement objects and methods to set Oracle performance extensions for any statement run in the current connection Implements |
|
Interface |
Provides methods to set Oracle performance extensions for individual statement Is a supertype of Implements |
|
Interface |
Provide Implements Extends Is a supertype of |
|
Interface |
Provides Implements Extends |
|
Interface |
Provides Implements |
|
Interface |
Provides methods to get meta information about Oracle result sets, such as column names and data types Implements |
|
Class |
Provides methods to get meta information about the database, such as database product name/version, table information, and default transaction isolation level Implements |
OracleTypes |
Class |
Defines integer constants used to identify SQL types For standard types, it uses the same values as the standard |
This section covers the following topics:
This interface extends standard JDBC connection functionality to create and return Oracle statement objects, set flags and options for Oracle performance extensions, support type maps for Oracle objects, and support client identifiers.
Client Identifiers
In a connection pooling environment, the client identifier can be used to identify which light-weight user is currently using the database session. A client identifier can also be used to share the Globally Accessed Application Context between different database sessions. The client identifier set in a database session is audited when database auditing is turned on.
Key methods include:
Allocates a new OracleStatement
object
Allocates a new OraclePreparedStatement
object
Allocates a new OracleCallableStatement
object
Retrieves the type map for this connection, for use in mapping Oracle object types to Java classes
Initializes or updates the type map for this connection, for use in mapping Oracle object types to Java classes
Gets this connection's current isolation mode
Changes the transaction isolation level using one of the TRANSACTION_*
values
The following oracle.jdbc.OracleConnection
methods are Oracle-defined extensions:
Sets the client identifier for this connection
Clears the client identifier for this connection
Retrieves the default update-batching value for this connection
Sets the default update-batching value for this connection
Retrieves the default row-prefetch value for this connection
Sets the default row-prefetch value for this connection
This interface extends standard JDBC statement functionality and is the superinterface of the OraclePreparedStatement
and OracleCallableStatement
classes. Extended functionality includes support for setting flags and options for Oracle performance extensions on a statement-by-statement basis, as opposed to the OracleConnection
interface that sets these on a connection-wide basis.
Key methods include:
Runs a database query and returns an OracleResultSet
object
Retrieves an OracleResultSet
object
Closes the current statement
The following oracle.jdbc.OracleStatement
methods are Oracle-defined extensions:
Defines the type you will use to retrieve data from a particular database table column
Note:
This method is no longer needed or recommended for use with the JDBC Thin driver.Retrieves the row-prefetch value for this statement
Sets the row-prefetch value for this statement
This interface extends the OracleStatement
interface and extends standard JDBC prepared statement functionality. Also, the oracle.jdbc.OraclePreparedStatement
interface is extended by the OracleCallableStatement
interface. Extended functionality consists of set
XXX
methods for binding oracle.sql.*
types and objects to prepared statements, and methods to support Oracle performance extensions on a statement-by-statement basis.
Note:
Do not usePreparedStatement
to create a trigger that refers to a :NEW
or :OLD
column. Use Statement
instead. Using PreparedStatement
will cause execution to fail with the message java.sql.SQLException: Missing IN or OUT parameter at index:: 1
Key methods include:
This method retrieves the update-batching value for this statement.
This method sets the update-batching value for this statement.
This is a generic set
XXX
method for binding oracle.sql.*
data to a prepared statement as an oracle.sql.Datum
object.
These methods, such as setBLOB
, are for binding specific oracle.sql.*
types to prepared statements.
set
XXX
AtName
Unlike the JDBC standard method set
XXX
(int,
XXX
)
, which sets the value of the nth SQL parameter specified by the integer argument, set
XXX
AtName(String,
XXX
)
sets the SQL parameter with the specified character name in the SQL string. The SQL parameter is a SQL identifier preceded by a colon (:
). For example, :id
in:
ps = conn.prepareStatement("select * from tab where id = :id"); ((OraclePreparedStatement)ps).setIntAtName("id", 42);
This method binds an ORAData
object to a prepared statement.
This method sets the value of the object specified by its SQL type name to NULL
. For setNull(
param_index
, type_code
, sql_type_name
), if type_code
is REF
, ARRAY
, or STRUCT
, then sql_type_name
is the fully qualified name of the SQL type.
setFormOfUse
This method sets which form of use this method is going to use. There are two constants that specify the form of use: FORM_CHAR
and FORM_NCHAR
, where FORM_CHAR
is the default, meaning that the regular database character set is used. If the form of use is set to FORM_NCHAR
, the JDBC driver will represent the provided data in the national character set of the server. The following code shows how the FORM_NCHAR
is used:
pstmt.setFormOfUse (parameter index, oracle.jdbc.OraclePreparedStatement.FORM_NCHAR)
This interface extends the OraclePreparedStatement
interface, which extends the OracleStatement
interface and incorporates standard JDBC callable statement functionality.
Note:
Do not useCallableStatement
to create a trigger that refers to a :NEW
or :OLD
column. Use Statement
instead; using CallableStatement
will cause execution to fail with the message java.sql.SQLException: Missing IN or OUT parameter at index::1
Key methods include:
This is a generic get
XXX
method for retrieving data into an oracle.sql.Datum
object, which can be cast to the specific oracle.sql.*
type as necessary.
These methods, such as getCLOB
, are for retrieving data into specific oracle.sql.*
objects.
This is a generic set
XXX
method for binding oracle.sql.*
data into a callable statement as an oracle.sql.Datum
object.
These methods, such as setBLOB
, are inherited from OraclePreparedStatement
for binding specific oracle.sql.*
objects into callable statements.
set
XXX
(String,
XXX
)
The definition of a PL/SQL stored procedure may include one or more named parameters. When you create a CallableStatement
to call this stored procedure, you must supply values for all IN parameters. You can either do this with the JDBC standard set
XXX
(int,
XXX
)
methods, or using the Oracle extension setXXX
(String,
XXX
)
. The first argument to this method specifies the name of the PL/SQL formal parameter and the second argument specifies the value. For example, consider a stored procedure foo
, defined as follows:
CREATE OR REPLACE PROCEDURE foo (myparameter VARCHAR2) IS BEGIN ... END;
Create an OracleCallableStatement
to call foo
, as follows:
OracleCallableStatement cs = (OracleCallableStatement) conn.prepareCall("{call foo(?)}");
You can pass the string "bar" to this procedure in one of the following two ways:
cs.setString(1,"bar"); // JDBC standard // or... cs.setString("myparameter","bar"); // Oracle extension
Note:
The argument is the name of the formal parameter declared in the PL/SQL stored procedure. This name does not necessarily appear anywhere in the SQL string. This differs from theset
XXX
AtName
method, whose first argument is a substring of the SQL string.set
XXX
AtName
Unlike the JDBC standard method set
XXX
(int,
XXX
)
, which sets the value of the nth SQL parameter specified by the integer argument, set
XXX
AtName(String,
XXX
)
sets the SQL parameter with the specified character name in the SQL string. The SQL parameter is a SQL identifier preceded by a colon (:
). For example, :id
in:
OracleCallableStatement cs = (OracleCallableStatement) conn.prepareCall("call foo(:id)"); cs.setIntAtName("id", 42);
This method sets the value of the object specified by its SQL type name to NULL
. For setNull(
param_index
, type_code
, sql_type_name
), if type_code
is REF
, ARRAY
, or STRUCT
, then sql_type_name
is the fully qualified name of the SQL type.
setFormOfUse
This method sets which form of use this method is going to use. There are two constants that specify the form of use: FORM_CHAR
and FORM_NCHAR
, where FORM_CHAR
is the default. If the form of use is set to FORM_NCHAR
, then the JDBC driver will represent the provided data in the national character set of the server. The following code show how FORM_NCHAR
is used:
pstmt.setFormOfUse (parameter index, oracle.jdbc.OraclePreparedStatement.FORM_NCHAR)
This method registers the SQL type code of the output parameter of the statement. JDBC requires this for any callable statement with an OUT
parameter. It takes an integer parameter index, the position of the output variable in the statement, relative to the other parameters, and an integer SQL type, the type constant defined in oracle.jdbc.OracleTypes
.
This is an overloaded method. One version of this method is for named types only, when the SQL type code is OracleTypes.REF
, STRUCT
, or ARRAY
. In this case, in addition to a parameter index and SQL type, the method also takes a String
SQL type name, the name of the Oracle user-defined type in the database, such as EMPLOYEE
.
This method closes the current result set, if any, and the current statement.
Notes:
The set
XXX
(String,...)
and registerOutParameter(String,...)
methods can only be used if all binds are procedure or function parameters only. The statement can contain no other binds and the parameter binds must be indicated with ?
and not :
XX
.
If you are using set
XXX
(int,...)
, set
XXX
AtName(String,...)
or a combination of both, then any output parameter is bound with registerOutParameter(int,...)
and not registerOutParameter(String,...)
, which is for named parameter notation.
This interface extends standard JDBC result set functionality, implementing get
XXX
methods for retrieving data into oracle.sql.*
objects.
Key methods include:
This interface extends standard JDBC result set metadata functionality to retrieve information about Oracle result set objects.
See Also:
"Using Result Set Meta Data Extensions"The OracleTypes
class defines constants that JDBC uses to identify SQL types. Each variable in this class has a constant integer value. The oracle.jdbc.OracleTypes
class duplicates the type code definitions of the standard Java java.sql.Types
class and contains these additional type codes for Oracle extensions:
OracleTypes.BFILE
OracleTypes.ROWID
OracleTypes.CURSOR
(for REF CURSOR
types)
As in java.sql.Types
, all the variable names are in uppercase.
JDBC uses the SQL types identified by the elements of the OracleTypes
class in two main areas: registering output parameters and in the setNull
method of the PreparedStatement
class.
OracleTypes and Registering Output Parameters
The type codes in java.sql.Types
or oracle.jdbc.OracleTypes
identify the SQL types of the output parameters in the registerOutParameter
method of the java.sql.CallableStatement
and oracle.jdbc.OracleCallableStatement
interfaces.
These are the forms that registerOutputParameter
can take for CallableStatement
and OracleCallableStatement
:
cs.registerOutParameter(int index, int sqlType); cs.registerOutParameter(int index, int sqlType, String sql_name); cs.registerOutParameter(int index, int sqlType, int scale);
In these signatures, index
represents the parameter index, sqlType
is the type code for the SQL data type, sql_name
is the name given to the data type, for user-defined types, when sqlType
is a STRUCT
, REF
, or ARRAY
type code, and scale
represents the number of digits to the right of the decimal point, when sqlType
is a NUMERIC
or DECIMAL
type code.
The following example uses a CallableStatement
to call a procedure named charout
, which returns a CHAR
data type. Note the use of the OracleTypes.CHAR
type code in the registerOutParameter
method.
CallableStatement cs = conn.prepareCall ("BEGIN charout (?); END;"); cs.registerOutParameter (1, OracleTypes.CHAR); cs.execute (); System.out.println ("Out argument is: " + cs.getString (1));
The next example uses a CallableStatement
to call structout
, which returns a STRUCT
data type. The form of registerOutParameter
requires you to specify the type code, Types.STRUCT
or OracleTypes.STRUCT
, as well as the SQL name, EMPLOYEE
.
The example assumes that no type mapping has been declared for the EMPLOYEE
type, so it is retrieved into a STRUCT
data type. To retrieve the value of EMPLOYEE
as an oracle.sql.STRUCT
object, the statement object cs
is cast to OracleCallableStatement
and the Oracle extension getSTRUCT
method is invoked.
CallableStatement cs = conn.prepareCall ("BEGIN structout (?); END;"); cs.registerOutParameter (1, OracleTypes.STRUCT, "EMPLOYEE"); cs.execute (); // get the value into a STRUCT because it // is assumed that no type map has been defined STRUCT emp = ((OracleCallableStatement)cs).getSTRUCT (1);
OracleTypes and the setNull Method
The type codes in Types
and OracleTypes
identify the SQL type of the data item, which the setNull
method sets to NULL
. The setNull
method can be found in the java.sql.PreparedStatement
and oracle.jdbc.OraclePreparedStatement
interfaces.
These are the forms that setNull
can take for PreparedStatement
and OraclePreparedStatement
objects:
ps.setNull(int index, int sqlType); ps.setNull(int index, int sqlType, String sql_name);
In these signatures, index
represents the parameter index, sqlType
is the type code for the SQL data type, and sql_name
is the name given to the data type, for user-defined types, when sqlType
is a STRUCT
, REF
, or ARRAY
type code. If you enter an invalid sqlType
, a ParameterTypeConflict
exception is thrown.
The following example uses a PreparedStatement
to insert a NULL
into the database. Note the use of OracleTypes.NUMERIC
to identify the numeric object set to NULL
. Alternatively, Types.NUMERIC
can be used.
PreparedStatement pstmt = conn.prepareStatement ("INSERT INTO num_table VALUES (?)"); pstmt.setNull (1, OracleTypes.NUMERIC); pstmt.execute ();
In this example, the prepared statement inserts a NULL
STRUCT
object of type EMPLOYEE
into the database.
PreparedStatement pstmt = conn.prepareStatement ("INSERT INTO employee_table VALUES (?)"); pstmt.setNull (1, OracleTypes.STRUCT, "EMPLOYEE"); pstmt.execute ();
The getJavaSqlConnection
method of the oracle.sql.* classes returns java.sql.Connection
while the getConnection
method returns oracle.jdbc.driver.OracleConnection
. Because the methods that use the oracle.jdbc.driver
package are deprecated, the getConnection
method is also deprecated in favor of the getJavaSqlConnection
method.
For the following Oracle data type classes, the getJavaSqlConnection
method is available:
oracle.sql.ARRAY
oracle.sql.BFILE
oracle.sql.BLOB
oracle.sql.CLOB
oracle.sql.OPAQUE
oracle.sql.REF
oracle.sql.STRUCT
The following shows the getJavaSqlConnection
and the getConnection
methods in the Array
class:
public class ARRAY { // New API // java.sql.Connection getJavaSqlConnection() throws SQLException; // Deprecated API. // oracle.jdbc.driver.OracleConnection getConnection() throws SQLException; ... }
DML returning provides richer functionality compared to retrieval of auto-generated keys. It can be used to retrieve not only auto-generated keys, but also other columns or values that the application may use.
Note:
The server-side internal driver does not support DML returning and retrieval of auto-generated keys.The following sections explain the support for DML returning:
See Also:
"Retrieval of Auto-Generated Keys"The OraclePreparedStatement
interface is enhanced with Oracle-specific application programming interfaces (APIs) to support DML returning. The following APIs are added to the oracle.jdbc.OraclePreparedStatement
interface, to register parameters that are returned and data retrieved by DML returning:
public void registerReturnParameter(int paramIndex, int externalType) throws SQLException; public void registerReturnParameter(int paramIndex, int externalType, int maxSize) throws SQLException; public void registerReturnParameter(int paramIndex, intsqlType, String typeName) throws SQLException; public ResultSet getReturnResultSet() throws SQLException;
The registerReturnParameter
method is used to register the return parameter for DML returning. The method throws an SQLException
instance if an error occurs. The paramIndex
parameter is used to specify the index of the return parameter. Its value should be greater than zero. The externalType
parameter specifies the type of the return parameter. The maxSize
parameter specifies the maximum bytes or characters of the return parameter. This method can be used only with char
or RAW
types. The typeName
parameter specifies the fully-qualified name of a SQL structured type.
Note:
If you do not know the maximum size of the return parameters, then you should useregisterReturnParameter(int paramIndex, int externalType)
, which picks the default maximum size. If you know the maximum size of return parameters, using registerReturnParameter(int paramIndex, int externalType, int maxSize)
can reduce memory consumption.The getReturnResultSet
method fetches the data returned from DML returning and returns it as a ResultSet
object. The method throws a SQLException
if an error occurs.
Note:
The Oracle-specific API for DML returning are inclasses12.jar
for Java Development Kit (JDK) 1.2.x and JDK 1.3.x and in ojdbc14.jar
for JDK 1.4.xBefore running a DML returning statement, the JDBC application needs to call one or more of the registerReturnParameter
methods. The method provides the JDBC drivers with information, such as type and size, of the return parameters. The DML returning statement is then processed using one of the standard JDBC APIs, executeUpdate
or execute
. You can then fetch the returned parameters as a ResultSet
object using the getReturnResultSet
method of the oracle.jdbc.OraclePreparedStatement
interface.
In order to read the values in the ResultSet
object, the underlying Statement
object must be open. When the underlying Statement
object is closed, the returned ResultSet
object is also closed. This is consistent with ResultSet
objects that are retrieved by processing SQL query statements.
When a DML returning statement is run, the concurrency of the ResultSet
object returned by the getReturnResultSet
method must be CONCUR_READ_ONLY
and the type of the ResultSet
object must be TYPE_FORWARD_ONLY
or TYPE_SCROLL_INSENSITIVE
.
This section provides two code examples of DML returning.
The following code example illustrates the use of DML returning. In this example, assume that the maximum size of the name
column is 100 characters. Because the maximum size of the name
column is known, the registerReturnParameter(int paramIndex, int externalType, int maxSize)
method is used.
... OraclePreparedStatement pstmt = (OraclePreparedStatement)conn.prepareStatement( "delete from tab1 where age < ? returning name into ?"); pstmt.setInt(1,18); /** register returned parameter * in this case the maximum size of name is 100 chars */ pstmt.registerReturnParameter(2, OracleTypes.VARCHAR, 100); // process the DML returning statement count = pstmt.executeUpdate(); if (count>0) { ResultSet rset = pstmt.getReturnResultSet(); //rest is not null and not empty while(rset.next()) { String name = rset.getString(1); ... } } ...
The following code example also illustrates the use of DML returning. However, in this case, the maximum size of the return parameters is not known. Therefore, the registerReturnParameter(int paramIndex, int externalType)
method is used.
... OraclePreparedStatement pstmt = (OraclePreparedStatement)conn.prepareStatement( "insert into lobtab values (100, empty_clob()) returning col1, col2 into ?, ?"); // register return parameters pstmt.registerReturnParameter(1, OracleTypes.INTEGER); pstmt.registerReturnParameter(2, OracleTypes.CLOB); // process the DML returning SQL statement pstmt.executeUpdate(); ResultSet rset = pstmt.getReturnResultSet(); int r; CLOB clob; if (rset.next()) { r = rset.getInt(1); System.out.println(r); clob = (CLOB)rset.getClob(2); ... } ...
When using DML returning, you need to be aware of the following:
It is unspecified what the getReturnResultSet
method returns when it is invoked more than once. You should not rely on any specific action in this regard.
The ResultSet
objects returned from the execution of DML returning statements do not support the ResultSetMetaData
type. Therefore, the applications need to know the information of return parameters before running DML returning statements.
Streams are not supported with DML returning.
DML returning cannot be combined with batch update.
You cannot use both the auto-generated key feature and the DML returning feature in a single SQL DML statement. For example, the following is not allowed:
... PreparedStatement pstmt = conn.prepareStatement('insert into orders (?, ?, ?) returning order_id into ?"); pstmt.setInt(1, seq01.NEXTVAL); pstmt.setInt(2, 100); pstmt.setInt(3, 966431502); pstmt.registerReturnParam(4, OracleTypes.INTEGER); pstmt.executeUpdate; ResultSet rset = pstmt.getGeneratedKeys; ...
The Oracle JDBC drivers enable JDBC applications to make PL/SQL calls with index-by table parameters. This section covers the following topics:
Note:
Index-by tables of PL/SQL records are not supported.The Oracle JDBC drivers support PL/SQL index-by tables of scalar data types. Table 5-3 displays the supported scalar types and the corresponding JDBC type codes.
Table 5-3 PL/SQL Types and Corresponding JDBC Types
PL/SQL Types | JDBC Types |
---|---|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Note:
Oracle JDBC does not supportRAW
, DATE
, and PL/SQL RECORD
as element types.Typical Oracle JDBC input binding, output registration, and data-access methods do not support PL/SQL index-by tables. This chapter introduces additional methods to support these types.
The OraclePreparedStatement
and OracleCallableStatement
classes define the additional methods. These methods include the following:
These methods handle PL/SQL index-by tables as IN
, OUT
, or IN OUT
parameters, including function return values.
To bind a PL/SQL index-by table parameter in the IN
parameter mode, use the setPlsqlIndexTable
method defined in the OraclePreparedStatement
and OracleCallableStatement
classes.
synchronized public void setPlsqlIndexTable (int paramIndex, Object arrayData, int maxLen, int curLen, int elemSqlType, int elemMaxLen) throws SQLException
Table 5-4 describes the arguments of the setPlsqlIndexTable
method.
Table 5-4 Arguments of the setPlsqlIndexTable Method
Argument | Description |
---|---|
Indicates the parameter position within the statement. |
|
Is an array of values to be bound to the PL/SQL index-by table parameter. The value is of type |
|
Specifies the maximum table length of the index-by table bind value that defines the maximum possible |
|
Specifies the actual size of the index-by table bind value in |
|
Specifies the index-by table element type based on the values defined in the |
|
Specifies the index-table element maximum length in case the element type is |
The following code example uses the setPlsqlIndexTable
method to bind an index-by table as an IN
parameter:
// Prepare the statement OracleCallableStatement procin = (OracleCallableStatement) conn.prepareCall ("begin procin (?); end;"); // index-by table bind value int[] values = { 1, 2, 3 }; // maximum length of the index-by table bind value. This // value defines the maximum possible "currentLen" for batch // updates. For standalone binds, "maxLen" should be the // same as "currentLen". int maxLen = values.length; // actual size of the index-by table bind value int currentLen = values.length; // index-by table element type int elemSqlType = OracleTypes.NUMBER; // index-by table element length in case the element type // is CHAR, VARCHAR or RAW. This value is ignored for other // types. int elemMaxLen = 0; // set the value procin.setPlsqlIndexTable (1, values, maxLen, currentLen, elemSqlType, elemMaxLen); // execute the call procin.execute ();
This section describes how to register a PL/SQL index-by table as an OUT
parameter. In addition, it describes how to access the OUT
bind values in various mapping styles.
Note:
The methods described in this section apply to function return values and theIN OUT
parameter mode as well.Registering the OUT Parameters
To register a PL/SQL index-by table as an OUT
parameter, use the registerIndexTableOutParameter
method defined in the OracleCallableStatement
class.
synchronized public void registerIndexTableOutParameter (int paramIndex, int maxLen, int elemSqlType, int elemMaxLen) throws SQLException
Table 5-5 describes the arguments of the registerIndexTableOutParameter
method.
Table 5-5 Arguments of the registerIndexTableOutParameter Method
Argument | Description |
---|---|
Indicates the parameter position within the statement. |
|
Specifies the maximum table length of the index-by table bind value to be returned. |
|
Specifies the index-by table element type based on the values defined in the |
|
Specifies the index-by table element maximum length in case the element type is |
The following code example uses the registerIndexTableOutParameter
method to register an index-by table as an OUT
parameter:
// maximum length of the index-by table value. This // value defines the maximum table size to be returned. int maxLen = 10; // index-by table element type int elemSqlType = OracleTypes.NUMBER; // index-by table element length in case the element type // is CHAR, VARCHAR or FIXED_CHAR. This value is ignored for other // types int elemMaxLen = 0; // register the return value funcnone.registerIndexTableOutParameter (1, maxLen, elemSqlType, elemMaxLen);
Accessing the OUT Parameter Values
To access the OUT
bind value, the OracleCallableStatement
class defines multiple methods that return the index-by table values in different mapping styles. There are three mapping choices available in JDBC drivers:
This section covers the following topics:
JDBC Default Mappings
The getPlsqlIndexTable(int)
method with returns index-by table elements using the JDBC default mappings. The syntax for this method is:
public Object getPlsqlIndexTable (int paramIndex) throws SQLException
Table 5-6 describes the argument of the getPlsqlIndexTable
method.
Table 5-6 Argument of the getPlsqlIndexTable Method
Argument | Description |
---|---|
This argument indicates the parameter position within the statement. |
The return value is a Java array. The elements of this array are of the default Java type corresponding to the SQL type of the elements. For example, for an index-by table with elements of NUMERIC
type code, the element values are mapped to BigDecimal
by the Oracle JDBC driver, and the getPlsqlIndexTable
method returns a BigDecimal[]
array. For a JDBC application, you must cast the return value to BigDecimal[]
to access the table element values.
The following code example uses the getPlsqlIndexTable
method to return index-by table elements with JDBC default mapping:
// access the value using JDBC default mapping BigDecimal[] values = (BigDecimal[]) procout.getPlsqlIndexTable (1); // print the elements for (int i=0; i<values.length; i++) System.out.println (values[i].intValue());
Oracle Mappings
The getOraclePlsqlIndexTable
method returns index-by table elements using Oracle mapping.
public Datum[] getOraclePlsqlIndexTable (int paramIndex) throws SQLException
Table 5-7 describes the argument of the getOraclePlsqlIndexTable
method.
Table 5-7 Argument of the getOraclePlsqlIndexTable Method
Argument | Description |
---|---|
Indicates the parameter position within the statement. |
The return value is an oracle.sql.Datum
array, and the elements in the array are of the default Datum
type corresponding to the SQL type of the element. For example, the element values of an index-by table of numeric elements are mapped to the oracle.sql.NUMBER
type in Oracle mapping, and the getOraclePlsqlIndexTable
method returns an oracle.sql.Datum
array that contains oracle.sql.NUMBER
elements.
The following code example uses the getOraclePlsqlIndexTable
method to access the elements of a PL/SQL index-by table OUT
parameter, using Oracle mapping.
// Prepare the statement OracleCallableStatement procout = (OracleCallableStatement) conn.prepareCall ("begin procout (?); end;"); ... // run the call procout.execute (); // access the value using Oracle JDBC mapping Datum[] outvalues = procout.getOraclePlsqlIndexTable (1); // print the elements for (int i=0; i<outvalues.length; i++) System.out.println (outvalues[i].intValue());
Java Primitive Type Mappings
The getPlsqlIndexTable(int, Class)
method returns index-by table elements in Java primitive types. The return value is a Java array. The syntax for this method is:
synchronized public Object getPlsqlIndexTable (int paramIndex, Class primitiveType) throws SQLException
Table 5-8 describes the arguments of the getPlsqlIndexTable
method.
Table 5-8 Arguments of the getPlsqlIndexTable Method
Argument | Description |
---|---|
Indicates the parameter position within the statement. |
|
Specifies a Java primitive type to which the index-by table elements are to be converted. For example, if you specify The following are the possible values of this parameter:
|
The following code example uses the getPlsqlIndexTable
method to access the elements of a PL/SQL index-by table of numbers. In the example, the second parameter specifies java.lang.Integer.TYPE
and the return value of the getPlsqlIndexTable
method is an int
array.
OracleCallableStatement funcnone = (OracleCallableStatement) conn.prepareCall ("begin ? := funcnone; end;"); // maximum length of the index-by table value. This // value defines the maximum table size to be returned. int maxLen = 10; // index-by table element type int elemSqlType = OracleTypes.NUMBER; // index-by table element length in case the element type // is CHAR, VARCHAR or RAW. This value is ignored for other // types int elemMaxLen = 0; // register the return value funcnone.registerIndexTableOutParameter (1, maxLen, elemSqlType, elemMaxLen); // execute the call funcnone.execute (); // access the value as a Java primitive array. int[] values = (int[]) funcnone.getPlsqlIndexTable (1, java.lang.Integer.TYPE); // print the elements for (int i=0; i<values.length; i++) System.out.println (values[i]);