JDBC's auto-generated keys feature provides a way to retrieve valuesfrom columns that are part of an index or have a default value assigned. Derby supports the auto-incrementfeature, which allows users to create columns in tables for which the databasesystem automatically assigns increasing integer values. Users can call the method Statement.getGeneratedKeys Where to buy parallels for mac. to retrieve the value of such a column. This method returns a ResultSet objectwith a column for the automatically generated key. Calling ResultSet.getMetaData onthe ResultSet object returned by getGeneratedKeys produces a ResultSetMetaData objectthat is similar to that returned by IDENTITY_VAL_LOCAL.
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If generated keys are requested on a table that has no auto increment column, the JDBC driver will return a null result set. When you insert rows by executeUpdate or execute an INSERT statement or an INSERT within SELECT statement, you need to indicate that you will want to retrieve automatically generated key values. You do that by setting a flag in a Connection.prepareStatement, Statement.executeUpdate,.
Users can indicate that auto-generated columns should be made availablefor retrieval by passing one of the following values as a second argumentto the Connection.prepareStatement, Statement.execute, or Statement.executeUpdate methods: Safari 6 download mac.
Example
Assume that we have a table TABLE1 definedas follows:
The following three code fragments will all do the same thing:that is, they will create a ResultSet that contains the value of C12 that is inserted into TABLE1.
Code fragment 1: Wifi hacking software for mac.
Jdbc Select And Get Generated Key Code
Code fragment 2:
Jdbc Select And Get Generated Key Download
Code fragment 3: Best tube downloader app for android.
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If there is no indication that auto-generated columns shouldbe made available for retrieval, a call to Statement.getGeneratedKeys will return a null ResultSet.
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The Microsoft JDBC Driver for SQL Server supports the optional JDBC 3.0 APIs to retrieve automatically generated row identifiers. The main value of this feature is to provide a way to make IDENTITY values available to an application that is updating a database table without a requiring a query and a second round-trip to the server.
Because SQL Server doesn't support pseudo columns for identifiers, updates that have to use the auto-generated key feature must operate against a table that contains an IDENTITY column. SQL Server allows only a single IDENTITY column per table. The result set that is returned by getGeneratedKeys method of the SQLServerStatement class will have only one column, with the returned column name of GENERATED_KEYS. If generated keys are requested on a table that has no IDENTITY column, the JDBC driver will return a null result set.
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As an example, create the following table in the sample database:
In the following example, an open connection to the sample database is passed in to the function, an SQL statement is constructed that will add data to the table, and then the statement is run and the IDENTITY column value is displayed.
Preparedstatement Return_generated_keysSee alsoComments are closed.
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