The Column Map must reside in the Optim™ Directory for the Destination or Source 2 subsystem. In most cases, you are connected to the Destination or Source 2 subsystem when defining a Column Map and would typically select a Source or Source 1 table from an Archive or Extract File used in the process for which the Column Map is defined. If a file is not available, you can select a database or Legacy Table as the source for column names. If you are processing data across DB2® subsystems, however, only a source table in an Archive or Extract File is available.
In certain circumstances, you may not have access to either the source table or the Archive or Extract File. If so, you can create a Column Map without identifying a source table and manually enter the column names that map to the Destination or Source 2 columns. Since Optim cannot reference definitions for the manually entered source columns, validation is performed during processing.
Leave the Use Source Columns From: prompts on the Specify Column Map Tables panel blank to indicate there is no source table. A prompt is displayed to confirm that a source table is not desired. Press Enter to proceed with the Column Map definition. Use END to return to the Specify Column Map Tables panel, where you can identify a source table.
When creating a Column Map manually, you can sometimes avoid errors and labor from typing source column names by using the CHANGE TABLES command to return to the Specify Column Map Tables panel. Enter the name of a table that has needed source column names and press Enter to return to the Column Map editor. Any previous Source Column entries are retained and you can use the LIST UNUSED or LIST ALL commands to select names of columns. You can use CHANGE TABLE and LIST several times to collect source column names from accessible tables to avoid typing each source column name.
For example, assume you do not have access to the source table and the destination table contains 100 columns. One method of inserting the source column names in the Column Map is to type the 100 entries. However, if an accessible table contains columns with 50 of the needed names, you can use CHANGE TABLE and specify this table as the source for the Column Map. Then, you can use LIST to insert the 50 names rather than type them. Also, if a second table includes another 25 columns with needed names, you can reuse CHANGE TABLE and LIST to include those names. In fact, since the destination table may include many of the needed source column names, you can specify it as the source in order to list those names in the Column Map.
Using CHANGE TABLE is a convenient way to avoid typing in names of source columns that are present in other tables. Note that you can turn validation off in order to save a Column Map created from several sources. See Validate Column Map for additional information.