org.apache.cayenne.dba.sybase

## Class SybasePkGenerator

- java.lang.Object
- - org.apache.cayenne.dba.JdbcPkGenerator
  - - org.apache.cayenne.dba.sybase.SybasePkGenerator

- All Implemented Interfaces:
    PkGenerator

      public class SybasePkGenerator
      extends JdbcPkGenerator

  Primary key generator implementation for Sybase. Uses a lookup table named "AUTO_PK_SUPPORT" and a stored procedure "auto_pk_for_table" to search and increment primary keys for tables.

- - ### Field Summary

    - ### Fields inherited from class org.apache.cayenne.dba.JdbcPkGenerator

      `adapter, DEFAULT_PK_CACHE_SIZE, pkCache, pkCacheSize, pkStartValue`

  - ### Constructor Summary

    Constructors
    Modifier | Constructor and Description
    --- | ---
    `protected` | `SybasePkGenerator(JdbcAdapter adapter)`

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `void` | `createAutoPk(DataNode node, List<DbEntity> dbEntities)` Generates database objects to provide automatic primary key support.
    `List<String>` | `createAutoPkStatements(List<DbEntity> dbEntities)` Returns a list of SQL strings needed to generates database objects to provide automatic primary support for the list of entities.
    `void` | `dropAutoPk(DataNode node, List<DbEntity> dbEntities)` Drops database objects related to automatic primary key support.
    `List<String>` | `dropAutoPkStatements(List<DbEntity> dbEntities)` Returns SQL string needed to drop database objects associated with automatic primary key generation.
    `protected long` | `longPkFromDatabase(DataNode node, DbEntity entity)` Performs primary key generation ignoring cache.
    `protected String` | `pkTableCreateString()`

    - ### Methods inherited from class org.apache.cayenne.dba.JdbcPkGenerator

      `autoPkTableExists, dropAutoPkString, generatePk, getAdapter, getPkCacheSize, pkCreateString, pkDeleteString, pkSelectString, pkUpdateString, reset, runUpdate, setPkCacheSize`

    - ### Methods inherited from class java.lang.Object

      `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

- - ### Constructor Detail

    - #### SybasePkGenerator

          protected SybasePkGenerator(JdbcAdapter adapter)

  - ### Method Detail

    - #### pkTableCreateString

          protected String pkTableCreateString()

      Overrides:
        `pkTableCreateString` in class `JdbcPkGenerator`

    - #### createAutoPk

          public void createAutoPk(DataNode node,
                                   List<DbEntity> dbEntities)
                            throws Exception

      Generates database objects to provide automatic primary key support. Method will execute the following SQL statements:

      1. Executed only if a corresponding table does not exist in the database.

              CREATE TABLE AUTO_PK_SUPPORT (
                 TABLE_NAME VARCHAR(32) NOT NULL,
                 NEXT_ID DECIMAL(19,0) NOT NULL
              )

      2. Executed under any circumstances.

           if exists (SELECT * FROM sysobjects WHERE name = 'auto_pk_for_table')
           BEGIN
              DROP PROCEDURE auto_pk_for_table
           END

      3. Executed under any circumstances.

      CREATE PROCEDURE auto_pk_for_table

           @tname VARCHAR(32),
           @pkbatchsize INT AS BEGIN BEGIN TRANSACTION UPDATE AUTO_PK_SUPPORT set NEXT_ID =
                        NEXT_ID +
           @pkbatchsize WHERE TABLE_NAME =
           @tname SELECT NEXT_ID from AUTO_PK_SUPPORT where NEXT_ID =
           @tname COMMIT END

      Specified by:
        `createAutoPk` in interface `PkGenerator`
      Overrides:
        `createAutoPk` in class `JdbcPkGenerator`
      Parameters:
        `node` - node that provides access to a DataSource.
        `dbEntities` - a list of entities that require primary key auto-generation support
      Throws:
        `Exception`

    - #### createAutoPkStatements

          public List<String> createAutoPkStatements(List<DbEntity> dbEntities)

      Description copied from interface: `PkGenerator`
      Returns a list of SQL strings needed to generates database objects to provide automatic primary support for the list of entities. No actual database operations are performed.
      Specified by:
        `createAutoPkStatements` in interface `PkGenerator`
      Overrides:
        `createAutoPkStatements` in class `JdbcPkGenerator`

    - #### dropAutoPk

          public void dropAutoPk(DataNode node,
                                 List<DbEntity> dbEntities)
                          throws Exception

      Drops database objects related to automatic primary key support. Method will execute the following SQL statements:

           if exists (SELECT * FROM sysobjects WHERE name = 'AUTO_PK_SUPPORT')
           BEGIN
              DROP TABLE AUTO_PK_SUPPORT
           END

           if exists (SELECT * FROM sysobjects WHERE name = 'auto_pk_for_table')
           BEGIN
              DROP PROCEDURE auto_pk_for_table
           END

      Specified by:
        `dropAutoPk` in interface `PkGenerator`
      Overrides:
        `dropAutoPk` in class `JdbcPkGenerator`
      Parameters:
        `node` - node that provides access to a DataSource.
        `dbEntities` - a list of entities whose primary key auto-generation support should be dropped.
      Throws:
        `Exception`

    - #### dropAutoPkStatements

          public List<String> dropAutoPkStatements(List<DbEntity> dbEntities)

      Description copied from interface: `PkGenerator`
      Returns SQL string needed to drop database objects associated with automatic primary key generation. No actual database operations are performed.
      Specified by:
        `dropAutoPkStatements` in interface `PkGenerator`
      Overrides:
        `dropAutoPkStatements` in class `JdbcPkGenerator`

    - #### longPkFromDatabase

          protected long longPkFromDatabase(DataNode node,
                                            DbEntity entity)
                                     throws Exception

      Description copied from class: `JdbcPkGenerator`
      Performs primary key generation ignoring cache. Generates a range of primary keys as specified by "pkCacheSize" bean property.

      This method is called internally from "generatePkForDbEntity" and then generated range of key values is saved in cache for performance. Subclasses that implement different primary key generation solutions should override this method, not "generatePkForDbEntity".

      Overrides:
        `longPkFromDatabase` in class `JdbcPkGenerator`
      Throws:
        `Exception`
      Since:
        3.0

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