- Connection.preparestatement(sql Statement.return_generated_keys)
- Preparedstatement.return_generated_keys
- Jdbc Statement.return_generated_keys
- Preparedstatement Return_generated_keys
Sep 09, 2015 Tour Start here for a quick overview of the site Help Center Detailed answers to any questions you might have Meta Discuss the workings and policies of this site. Nov 01, 2017 Yes, There is a way. I just found this hiding in the java doc. They way is to pass the AutoGeneratedKeys id as follows. String sql = 'INSERT INTO table (column1, column2) values(?,?)'; stmt = conn.prepareStatement(sql, Statement.RETURNGENERATEDKEYS). An interface for a precompiled SQL Statement. An SQL Statement is put into a PreparedStatement and is precompiled so that it can be executed efficiently multiple times.
Oracle Java Database Connectivity (JDBC) supports several different versions of JDBC, including JDBC 2.0 and 3.0. This chapter provides an overview of JDBC 2.0 and JDBC 3.0 support in the Oracle JDBC drivers. The chapter contains the following sections:
Is there a way to retrieve the auto generated key from a DB query when using a java query with prepared statements. For example, I know AutoGeneratedKeys can work as follows. Summary: in this tutorial, you will learn how to insert data into a table in the PostgreSQL database using JDBC API. We will use the actor table in the sample database for the demonstration. Inserting one row into a table. To insert a row into a table, you follow these steps: Establish a database connection to get a Connection object. だからこそconn.prepareStatement(sql, Statement.RETURNGENERATEDKEYS)という解決策が私のためにjava.lang.AbstractMethodErrorを投げたのです。 この状況で、私が見つけた可能性のある解決策は、Microsoftが提案した古い解決策です。JDBCを使用して@@ IDENTITY値を取得する方法.
Introduction
The Oracle JDBC drivers support all JDBC 3.0 features. These features are provided through the
oracle.jdbc
and oracle.sql
packages. These packages support all Java Development Kit (JDK) releases from 1.2 through 1.4. JDBC 3.0 features that depend on JDK1.4 are made available to earlier JDK versions through Oracle extensions.JDBC 2.0 Support: JDK 1.2.x and Later Versions
Standard JDBC 2.0 features are supported by JDK 1.2 and later versions. There are three areas to consider:
- Support for data types, such as objects, arrays, and large objects (LOBs). This is handled through the standard
java.sql
package. - Support for standard features, such as result set enhancements and update batching. This is handled through standard objects, such as
Connection
,ResultSet
, andPreparedStatement
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This section covers the following topics:
Note:
JDK1.1.x is no longer supported. The package oracle.jdbc2
has been removed.Data Type Support
Oracle JDBC fully supports JDK 1.2.x, which includes standard JDBC 2.0 functionality through implementation of interfaces in the standard
java.sql
package. These interfaces are implemented as appropriate by classes in the oracle.sql
and oracle.jdbc
packages.Standard Feature Support
In a JDK 1.2.x environment, using the JDBC classes in
classes12.jar
, JDBC 2.0 features, such as scrollable result sets, updatable result sets, and update batching, are supported through methods specified by standard JDBC 2.0 interfaces.Extended Feature Support
Features of the JDBC 2.0 optional package, including data sources, connection pooling, and distributed transactions, are supported in a JDK 1.2.x or later environment.
The standard
javax.sql
package and classes that implement its interfaces are included in the Java Archive (JAR) files packaged with the Oracle Database.Standard versus Oracle Performance Enhancement APIs
The following performance enhancements are available under JDBC 2.0, which had previously been available as Oracle extensions:
- Update batching
- Fetch size or row prefetching
In each case, you have the option of using the standard model or the Oracle model. Do not, however, try to mix usage of the standard model and Oracle model within a single application for either of these features.
See Also:
JDBC 3.0 Support: JDK 1.4 and Previous Releases
Table 4-1 lists the interfaces and classes added or extended to support specific JDBC features. Adobe premiere pro cc 2018 key generator.
Table 4-1 JDBC 3.0 Feature Support
New feature | JDK1.4 implementation | Pre-JDK1.4 implementation |
---|---|---|
Savepoints (new class) | java.sql.Savepoint | oracle.jdbc.OracleSavepoint |
Savepoints (connection extensions) | java.sql.connection | oracle.jdbc.OracleConnection |
Querying parameter capacities (new class) | java.sql.ParameterMetaData | oracle.jdbc.OracleParameterMetaData |
Querying parameter capacities (interface change) | Not applicable | oracle.jdbc.OraclePreparedStatement |
Resource adapters | oracle.jdbc.connector | oracle.jdbc.connector |
RowSets | oracle.jdbc.rowset | oracle.jdbc.rowset |
LOB modification | Not applicable | oracle.sql.BLOB oracle.sql.CLOB |
Retrieving auto-generated keys | oracle.sql.Statement | oracle.jdbc.OracleStatement oracle.jdbc.OracleConnection |
Result set holdability | java.sql.Connection java.sql.DatabaseMetaData java.sql.Statement | oracle.jdbc.OracleConnection oracle.jdbc.OracleDatabaseMetadata oracle.jdbc.OracleStatement |
Overview of Supported JDBC 3.0 Features
Table 4-2 lists the JDBC 3.0 features supported at this release and gives references to a detailed discussion of each feature.
Table 4-2 Key Areas of JDBC 3.0 Functionality
Feature | Comments and References |
---|---|
Transaction savepoints | See 'Transaction Savepoints' for information. |
Statement caching | Reuse of prepared statements by connection pools. See Chapter 22, 'Statement Caching'. |
Switching between local and global transactions | See 'Switching Between Global and Local Transactions'. |
LOB modification | See 'JDBC 3.0 LOB Interface Methods' . |
Named SQL parameters | See 'Interface oracle.jdbc.OracleCallableStatement' and 'Interface oracle.jdbc.OraclePreparedStatement' . |
RowSets | See Chapter 20, 'JDBC RowSets' |
Retrieving auto-generated keys | See 'Retrieval of Auto-Generated Keys' |
Result set holdability | See 'Result Set Holdability' |
Transaction Savepoints
The JDBC 3.0 specification supports savepoints, which offer finer demarcation within transactions. Applications can set a savepoint within a transaction and then roll back all work done after the savepoint. Savepoints relax the atomicity property of transactions. A transaction with a savepoint is atomic in the sense that it appears to be a single unit outside the context of the transaction, but code operating within the transaction can preserve partial states.
Note:
Savepoints are supported for local transactions only. Specifying a savepoint within a global transaction causes SQLException
to be thrown.JDK1.4 specifies a standard savepoint API. Oracle JDBC provides the following different savepoint interfaces:
java.sql.Savepoint
Works with JDK1.4oracle.jdbc.OracleSavepoint
Works across all supported JDK versions.
JDK1.4 adds savepoint-related APIs to
java.sql.Connection
. The Oracle JDK version-independent interface, oracle.jdbc.OracleConnection
, provides equivalent functionality.Creating a Savepoint
You create a savepoint using either
Connection.setSavepoint
, which returns a java.sql.Savepoint
instance, or OracleConnection.oracleSetSavepoint
, which returns an oracle.jdbc.OracleSavepoint
instance.A savepoint is either named or unnamed. You specify the name of a savepoint by supplying a string to the
setSavepoint
method. If you do not specify a name, then the savepoint is assigned an integer ID. You retrieve a name using getSavepointName()
. You retrieve an ID using getSavepointId()
.Note:
Attempting to retrieve a name from an unnamed savepoint or attempting to retrieve an ID from a named savepoint throws an SQLException
.Rolling back to a Savepoint
Connection.preparestatement(sql Statement.return_generated_keys)
You roll back to a savepoint using
Connection.rollback(Savepoint svpt)
or OracleConnection.oracleRollback(OracleSavepoint svpt)
. If you try to roll back to a savepoint that has been released, then SQLException
is thrown.Releasing a Savepoint
You remove a savepoint using one of the following methods:
Connection.releaseSavepoint(Savepoint svpt)
OracleConnection.oracleReleaseSavepoint(OracleSavepoint svpt)
Note:
As of Oracle Database 10g, releaseSavepoint
and oracleReleaseSavepoint
are not supported. If you call either of the methods, then SQLException
is thrown with the message 'Unsupported feature'.Checking Savepoint Support
You query whether savepoints are supported by your database by calling
oracle.jdbc.OracleDatabaseMetaData.supportsSavepoints()
, which returns true
if savepoints are available, false
otherwise.Savepoint Notes
When using savepoints, you must consider the following:
- After a savepoint has been released, attempting to reference it in a rollback operation will cause an
SQLException
to be thrown. - When a transaction is committed or rolled back, all savepoints created in that transaction are automatically released and become invalid.
- Rolling a transaction back to a savepoint automatically releases and makes invalid any savepoints created after the savepoint in question.
Savepoint Interfaces
The following methods are used to get information from savepoints. These methods are defined within both the
java.sql.Connection
and oracle.jdbc.OracleSavepoint
interfaces:public int getSavepointId() throws SQLException;
Returns the savepoint ID for an unnamed savepoint. ThrowsSQLException
ifself
is a named savepoint.public String getSavepointName() throws SQLException;
Returns the name of a named savepoint. ThrowsSQLException
ifself
is an unnamed savepoint.
The following methods are defined within the
java.sql.Connection
interface:public Savepoint setSavepoint() throws SQLException;
Creates an unnamed savepoint. ThrowsSQLException
on database error or if connection is in the auto-commit mode or participating in a global transaction.public Savepoint setSavepoint(String name) throws SQLException;
Creates a named savepoint. If a savepoint by this name already exists, then this instance replaces it. ThrowsSQLException
on database error or if connection is in the auto-commit mode or participating in a global transaction.public void rollback(Savepoint savepoint) throws SQLException;
Removes specified savepoint from current transaction. Any references to the savepoint after it is removed cause anSQLException
to be thrown. ThrowsSQLException
on database error or if connection is in the auto-commit mode or participating in a global transaction.public void releaseSavepoint(Savepoint savepoint) throws SQLException;
Not supported at this release. Always throwsSQLException
.
Pre-JDK1.4 Savepoint Support
The following methods are defined within the
oracle.jdbc.OracleConnection
interface. Except for using OracleSavepoint
in the signatures, they are identical to the methods declared in the preceding section.Retrieval of Auto-Generated Keys
Many database systems automatically generate a unique key field when a row is inserted. Oracle Database provides the same functionality with the help of sequences and triggers. JDBC 3.0 introduces the retrieval of auto-generated keys feature that enables you to retrieve such generated values. In JDBC 3.0, the following interfaces are enhanced to support the retrieval of auto-generated keys feature:
These interfaces provide methods that support retrieval of auto-generated keys. However, this feature is supported only when
INSERT
statements are processed. Other data manipulation language (DML) statements are processed, but without retrieving auto-generated keys.Note:
The Oracle server-side internal driver does not support the retrieval of auto-generated keys feature.java.sql.DatabaseMetaData
Preparedstatement.return_generated_keys
In JDBC 3.0, the
java.sql.DatabaseMetaData
interface provides the following method:The method indicates whether retrieval of auto-generated keys is supported or not by the JDBC driver and the underlying data source.
java.sql.Statement
The
java.sql.Statement
interface is enhanced with the following methods:This interface provides new methods for processing SQL statements and retrieving auto-generated keys. These methods take a String object that contains a SQL statement. They also take either the flag,
Statement.RETURN_GENERATED_KEYS
, indicating whether any generated columns are to be returned, or an array of column names or indexes specifying the columns that should be returned. The flag and the array values are considered only when an INSERT
statement is processed. If an UPDATE
or DELETE
statement is processed, these values are ignored.The
getGeneratedKeys()
method enables you to retrieve the auto-generated key fields. The auto-generated keys are returned as a ResultSet object.If key columns are not explicitly indicated, then Oracle JDBC drivers cannot identify which columns need to be retrieved. When a column name or column index array is used, Oracle JDBC drivers can identify which columns contain auto-generated keys that you want to retrieve. However, when the
Statement.RETURN_GENERATED_KEYS
integer flag is used, Oracle JDBC drivers cannot identify these columns. When the integer flag is used to indicate that auto-generated keys are to be returned, the ROWID
pseudo column is returned as key. The ROWID
can be then fetched from the ResultSet object and can be used to retrieved other columns.java.sql.Connection
The
java.sql.Connection
interface is enhanced with the following methods:These methods enable you to create a
PreparedStatement
object that is capable of returning auto-generated keys.Sample Code
The following code illustrates retrieval of auto-generated keys:
In the preceding example, a sequence,
SEQ01
, is created to generate values for the ORDER_ID
column starting from 1000
and incrementing by 1
each time the sequence is processed to generated the next value. An OraclePreparedStatement
object is created to insert a row in to the ORDERS
table.JDBC 3.0 LOB Interface Methods
Before Oracle Database 10g release 2 (10.2), Oracle provided proprietary interfaces for modification of LOB data. JDBC 3.0 adds methods for these operations. In Oracle9i Database release 2, the JDBC 3.0 methods were present in
ojdbc14.jar
, but were not functional. The JDBC 3.0 standard LOB methods differ slightly in name and function from the Oracle proprietary ones. In Oracle Database 10g release 2 (10.2), the JDBC 3.0 standard methods are implemented in both ojdbc14.jar
and classes12.jar
. In order to use these methods with JDK1.2 or 1.3, LOB variables must be typed as, or cast to, oracle.sql.BLOB
or oracle.sql.CLOB
as appropriate. With JDK1.4, LOB variables may be typed as java.sql.Blob
or java.sql.Clob
.Table 4-3 and Table 4-4 show the conversions between Oracle proprietary methods and JDBC 3.0 standard methods.
Table 4-3 BLOB Method Equivalents
Oracle Proprietary Method | JDBC 3.0 Standard Method |
---|---|
putBytes(long pos, byte [] bytes) | setBytes(long pos, byte[] bytes) |
putBytes(long pos, byte [] bytes, int length) | setBytes(long pos, byte[] bytes, int offset, int len) |
getBinaryOutputStream(long pos) | setBinaryStream(long pos) |
trim (long len) | truncate(long len) |
Table 4-4 CLOB Method Equivalents
Oracle Proprietary Method | JDBC 3.0 Standard Method |
---|---|
putString(long pos, String str) | setString(long pos, String str) |
not applicable | setString(long pos, String str, int offset, int len) |
getAsciiOutputStream(long pos) | setAsciiStream(long pos) |
getCharacterOutputStream(long pos) | setCharacterStream(long pos) |
trim (long len) | truncate(long len) |
Result Set Holdability
Result set holdability is a new feature introduced in JDBC 3.0. This feature enables applications to decide whether the
ResultSet
objects should be open or closed, when a commit operation is performed. The commit operation could be either implicit or explicit.The default holdability property of a
ResultSet
object is implementation defined. The default holdability of ResultSet
objects returned by the underlying data source can be determined using the APIs provided by JDBC 3.0.Jdbc Statement.return_generated_keys
In JDBC 3.0, the following APIs have been modified to support this feature:
java.sql.Connection
java.sql.DatabaseMetaData
java.sql.Statement
JDBC 3.0 also provides two new ResultSet constants:
ResultSet.HOLD_CURSORS_OVER_COMMIT
ResultSet.CLOSE_CURSORS_AT_COMMIT
Oracle Database only supports
HOLD_CURSORS_OVER_COMMIT
. Therefore, it is the default value for the Oracle JDBC drivers. Any attempt to change holdability will throw SQLException
.- JDBC Tutorial
- JDBC Examples
- JDBC Useful Resources
- Selected Reading
Once a connection is obtained we can interact with the database. The JDBC Statement, CallableStatement, and PreparedStatement interfaces define the methods and properties that enable you to send SQL or PL/SQL commands and receive data from your database.
They also define methods that help bridge data type differences between Java and SQL data types used in a database.
The following table provides a summary of each interface's purpose to decide on the interface to use.
Interfaces | Recommended Use |
---|---|
Statement | Use this for general-purpose access to your database. Useful when you are using static SQL statements at runtime. The Statement interface cannot accept parameters. |
PreparedStatement | Use this when you plan to use the SQL statements many times. The PreparedStatement interface accepts input parameters at runtime. |
CallableStatement | Use this when you want to access the database stored procedures. The CallableStatement interface can also accept runtime input parameters. |
The Statement Objects
Creating Statement Object
Before you can use a Statement object to execute a SQL statement, you need to create one using the Connection object's createStatement( ) method, as in the following example −
Once you've created a Statement object, you can then use it to execute an SQL statement with one of its three execute methods.
- boolean execute (String SQL): Returns a boolean value of true if a ResultSet object can be retrieved; otherwise, it returns false. Use this method to execute SQL DDL statements or when you need to use truly dynamic SQL.
- int executeUpdate (String SQL): Returns the number of rows affected by the execution of the SQL statement. Use this method to execute SQL statements for which you expect to get a number of rows affected - for example, an INSERT, UPDATE, or DELETE statement.
- ResultSet executeQuery (String SQL): Returns a ResultSet object. Use this method when you expect to get a result set, as you would with a SELECT statement.
Closing Statement Object
Just as you close a Connection object to save database resources, for the same reason you should also close the Statement object.
A simple call to the close() method will do the job. If you close the Connection object first, it will close the Statement object as well. However, you should always explicitly close the Statement object to ensure proper cleanup.
For a better understanding, we suggest you to study the Statement - Example tutorial.
The PreparedStatement Objects
The PreparedStatement interface extends the Statement interface, which gives you added functionality with a couple of advantages over a generic Statement object.
This statement gives you the flexibility of supplying arguments dynamically.
Creating PreparedStatement Object
All parameters in JDBC are represented by the ? symbol, which is known as the parameter marker. You must supply values for every parameter before executing the SQL statement.
The setXXX() methods bind values to the parameters, where XXX represents the Java data type of the value you wish to bind to the input parameter. If you forget to supply the values, you will receive an SQLException.
Each parameter marker is referred by its ordinal position. The first marker represents position 1, the next position 2, and so forth. This method differs from that of Java array indices, which starts at 0.
All of the Statement object's methods for interacting with the database (a) execute(), (b) executeQuery(), and (c) executeUpdate() also work with the PreparedStatement object. However, the methods are modified to use SQL statements that can input the parameters.
Closing PreparedStatement Object
Preparedstatement Return_generated_keys
Just as you close a Statement object, for the same reason you should also close the PreparedStatement object.
A simple call to the close() method will do the job. If you close the Connection object first, it will close the PreparedStatement object as well. However, you should always explicitly close the PreparedStatement object to ensure proper cleanup.
For a better understanding, let us study Prepare - Example Code.
The CallableStatement Objects
Just as a Connection object creates the Statement and PreparedStatement objects, it also creates the CallableStatement object, which would be used to execute a call to a database stored procedure.
Creating CallableStatement Object
Suppose, you need to execute the following Oracle stored procedure −
NOTE: Above stored procedure has been written for Oracle, but we are working with MySQL database so, let us write same stored procedure for MySQL as follows to create it in EMP database −
Three types of parameters exist: IN, OUT, and INOUT. The PreparedStatement object only uses the IN parameter. The CallableStatement object can use all the three.
Here are the definitions of each −
Parameter | Description |
---|---|
IN | A parameter whose value is unknown when the SQL statement is created. You bind values to IN parameters with the setXXX() methods. |
OUT | A parameter whose value is supplied by the SQL statement it returns. You retrieve values from theOUT parameters with the getXXX() methods. |
INOUT | A parameter that provides both input and output values. You bind variables with the setXXX() methods and retrieve values with the getXXX() methods. |
The following code snippet shows how to employ the Connection.prepareCall() method to instantiate a CallableStatement object based on the preceding stored procedure −
The String variable SQL, represents the stored procedure, with parameter placeholders.
Using the CallableStatement objects is much like using the PreparedStatement objects. You must bind values to all the parameters before executing the statement, or you will receive an SQLException.
If you have IN parameters, just follow the same rules and techniques that apply to a PreparedStatement object; use the setXXX() method that corresponds to the Java data type you are binding.
When you use OUT and INOUT parameters you must employ an additional CallableStatement method, registerOutParameter(). The registerOutParameter() method binds the JDBC data type, to the data type that the stored procedure is expected to return.
Once you call your stored procedure, you retrieve the value from the OUT parameter with the appropriate getXXX() method. This method casts the retrieved value of SQL type to a Java data type.
Closing CallableStatement Object
Just as you close other Statement object, for the same reason you should also close the CallableStatement object.
A simple call to the close() method will do the job. If you close the Connection object first, it will close the CallableStatement object as well. However, you should always explicitly close the CallableStatement object to ensure proper cleanup.
For a better understanding, I would suggest to study Callable - Example Code.