Partitioning key

In DB2 Universal Database Extended Enterprise Edition a partitioning key is an ordered set of one or more columns in a given table. For each row in the table, the values in the partitioning key columns are used to determine on which database partition the row belongs.

No LOB, LONG VARCHAR, or LONG VARGRAPHIC columns may be used as part of a partitioning key.

If you do not identify a partitioning key when you create a table that resides in a multinode nodegroup, one of three actions will occur by default:

• The table will be created and, if you specified a primary key, the partitioning key will be the first column of the primary key.

• The table will be created and, if you did not specify a primary key, the partitioning key will be the first non-long column (LOB or long column type).

• The table will not be created if there are only LOB or long columns and you did not specify a primary key.

If you do not identify a partitioning key when you create a table that resides in a single-node nodegroup, the table is created without a partitioning key. You can add or alter the partitioning key after the table is created.

For more information on choosing columns for the partitioning key, see Data Partitioning Across Multiple Partitions in the SQL Reference.

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