Fragmenting a Table Using an Expression Distribution Scheme

An expression-based distribution scheme distributes table data across multiple dbspaces according to conditions that you define.

To fragment a table using the expression scheme

1. In the Table Editor, click the General tab.
   
2. Select Fragmented from the Table Location list box.
   
3. Select Expression from the Distribution Scheme list box.
   The Expression grid appears, with an empty row. If there is no empty row, then all dbspaces are currently being used by the table.
   
4. Click an empty row in the DBSpace column of the Expression grid to add dbspaces.
   A DBSpaces drop-down list box appears, listing the dbspaces that are not used by the table.
5. Select the appropriate dbspace and repeat, as necessary.
   
6. Enter the expression definition for each dbspace in the Expression column.
   
7. In the Remainder DBSpaces drop-down list box, select the dbspace in which to store the table rows that are not defined in the expression definitions.
   (Only the dbspaces that are not specified in the DBSpace column of the Expression grid are listed.)
   
8. Choose Table->Execute to save the table to the database.

Tips

• Each dbspace in the Expression grid must have a definition. The expression definition must contain columns from the current table and data values from a single row. Subqueries, stored procedures, date and time functions, and aggregates are not allowed in an expression definition. The maximum length is 256 bytes.
• If an expression distribution scheme is specified and the columns are renamed, the Table Editor reloads the table and index after the table is saved.
• If you change or add expressions to the table's fragmentation scheme and rename columns before saving the table, you must use the new column names in all of the expressions.