Cheers, Martin On Fri, Nov 2, 2012 at 10:17 AM, Peter Backlund <[login to unmask email]>wrote: > In DB2 for z/OS there is a possibility - Create Unique Index Where Not > Null > For more information, see Create Unique Indexes. I am trying to create a unique index for a subset of data in a particular table.

Pour plus d’informations, consultez Créer des index uniques. Otherwise, the index is not unique and multiple rows can share the same key value. As can be seen clearly from the output, the SYS_C007876 unique index was created automatically with the generated name.. To specify the name for the primary key column, you use the UNIQUE index as shown in the following query:. However, in contrast, if you have a column that has a "unique constraint" then DB2 forces that column to be "not-null".

Les index d'une table ou d'une vue sont automatiquement conservés à chaque fois que les données de la table sont modifiées. CREATE TABLE t2 ( pk2 INT PRIMARY KEY USING INDEX ( CREATE INDEX t1_pk1_i ON t2 (pk2) ), c2 INT); .

create unique index u_idx_bank_emp on bank_employee(emp_id); Here, we are creating a unique index for EMP_ID and unique index name is “U_IDX_BANK_EMP”.

Db2 requires any column in either a primary-key or a unique-key to be mandatory (not null). P: n/a Knut Stolze. So DB2 lets you create a "unique index" on a nullable column. In this example, we explicitly specified the name of the unique index. Any other index change is done simply by drop/create.

Nov 12 '05 #4. Also, you may notice that the ALTER INDEX statement is somewhat new, because the only option relates to compression.