发行说明

15.11 Chapter 10. Capture and Apply for OS/390

在第 10 章中，更新了下列段落：

|15.11.1 Prerequisites for DB2 DataPropagator for OS/390

|You must have DB2 for OS/390 Version 5, DB2 for OS/390 Version 6, or DB2 |for OS/390 Version 7 to run DB2 DataPropagator for OS/390 Version 7 (V7).

|15.11.2 UNICODE and ASCII Encoding Schemes on OS/390

|DB2 DataPropagator for OS/390 V7 supports UNICODE and ASCII encoding schemes. |To exploit the new encoding schemes, you must have DB2 for OS/390 V7 and you |must manually create or convert your DB2 DataPropagator source, target, and |control tables as described in the following sections. However, your existing |replication environment will work with DB2 DataPropagator for OS/390 V7 even |if you do not modify any encoding schemes.

|15.11.2.1 Choosing an Encoding Scheme

|If your source, CD, and target tables use the same encoding scheme, you |can minimize the need for data conversions in your replication environment. |When you choose encoding schemes for the tables, follow the single CCSID rule: |Character data in a table space can be encoded in ASCII, UNICODE, or EBCDIC. |All tables within a table space must use the same encoding scheme. The encoding |scheme of all the tables in an SQL statement must be the same. Also, all |tables that you use in views and joins must use the same encoding scheme.

|If you do not follow the single CCSID rule, DB2 will detect the violation |and return SQLCODE -873 during bind or execution. Which tables should be ASCII |or UNICODE depends on your client/server configuration. Specifically, follow |these rules when you choose encoding schemes for the tables:

• |Source or target tables on DB2 for OS/390 can be EBCDIC, ASCII, or UNICODE. |They can be copied from or to tables that have the same or different encoding |scheme in any supported DBMS (DB2 family, or non-DB2 with DataJoiner).
• |On a DB2 for OS/390 source server, all CD, UOW, register, and prune control |tables on the same server must use the same encoding scheme. To ensure this |consistency, always specify the encoding scheme explicitly.
• |All the control tables (ASN.IBMSNAP_SUBS_xxxx) on the same control server |must use the same encoding scheme.
• |Other control tables can use any encoding scheme; however, it is recommended |that the ASN.IBMSNAP_CRITSEC table remain EBCDIC. |

|15.11.2.2 Setting Encoding Schemes

|To specify the proper encoding scheme for tables, modify the SQL that is |used to generate the tables:

• |Create new source and target tables with the proper encoding scheme, or |change the encoding schemes of the existing target and source tables. It is |recommended that you stop the Capture and Apply programs before you change |the encoding scheme of existing tables, and afterwards that you cold start |the Capture program and restart the Apply program. To change the encoding |scheme of existing tables:
  1. |Use the Reorg utility to copy the existing table.
  2. |Drop the existing table.
  3. |Re-create the table specifying the new encoding scheme.
  4. |Use the Load utility to load the old data into the new table. |

  |See the DB2 Universal Database |for OS/390 Utility Guide and Reference for more information on the Load and Reorg utilities.

• |Create new control tables with the proper encoding scheme or modify the |encoding scheme for existing ones.

  |DPCNTL.MVS is shipped with DB2 for OS/390 |in sqllib\samples\repl and it contains several CREATE TABLE statements |that create the control tables. For those tables that need to be ASCII or |UNICODE (for example, ASN.IBMSNAP_REGISTER and ASN.IBMSNAP_PRUNCNTL), add |the CCSID ASCII or CCSID UNICODE keyword, as shown in the following example.

  |CREATE TABLE ASN.IBMSNAP_PRUNCNTL (
  |  TARGET_SERVER      CHAR( 18)              NOT NULL,
  |  TARGET_OWNER       CHAR( 18)              NOT NULL,
  |  TARGET_TABLE       CHAR( 18)              NOT NULL,
  |  SYNCHTIME          TIMESTAMP,
  |  SYNCHPOINT         CHAR( 10)              FOR BIT DATA,
  |  SOURCE_OWNER       CHAR( 18)              NOT NULL,
  |  SOURCE_TABLE       CHAR( 18)              NOT NULL,
  |  SOURCE_VIEW_QUAL   SMALLINT               NOT NULL,
  |  APPLY_QUAL         CHAR( 18)              NOT NULL,
  |  SET_NAME           CHAR( 18)              NOT NULL,
  |  CNTL_SERVER        CHAR( 18)              NOT NULL,
  |  TARGET_STRUCTURE   SMALLINT               NOT NULL,
  |  CNTL_ALIAS         CHAR(  8)
  |        )  CCSID UNICODE
  |           DATA CAPTURE CHANGES
  |           IN TSSNAP02;

  |To modify existing control tables and CD tables, |use the Reorg and Load utilities.

• |When you create new replication sources or subscription sets, modify the |SQL file generated by the administration tool to specify the proper encoding |scheme. The SQL has several CREATE TABLE statements that are used to create |the CD and target tables for the replication source and subscription set, |respectively. Add the keyword CCSID ASCII or CCSID UNICODE where appropriate. |For example:

  |CREATE TABLE   user1.cdtable1 (
  |  employee_name   varchar,
  |  employee_age    decimal
  |    )  CCSID UNICODE; 

  |The DB2 UDB for OS/390 SQL |Reference contains more information about CCSID. |