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Dbms Okkkk Prema 04-16-2019 12:04 AM

Unique index When a primary key is defined in the table, DBMS automatically creates a unique index on a primary key column. Indexes play an important role in DBMS for the implementation of primary keys. When you define a table's primary key, the DBMS automatically creates a unique index on the primary key column you declared. In a unique index as its name implies, the index key can have only one pointer value (row) associated with it. Indexes can be unique or non-unique. Unique indexes guarantee that no two rows of a table have duplicate values in the key column (or columns). Non-unique indexes do not impose this restriction on the column values. Use the CREATE UNIQUE INDEX statement to create a unique index. Prajakta Pandit 03-15-2017 03:34 AM

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