SQL/MX 2.x Reference Manual (H06.04+)

SQL/MX Language Elements

HP NonStop SQL/MX Reference Manual—540440-003

6-55

Indexes

An index is an ordered set of pointers to rows of a table. Each index is based on the

values in one or more columns. An index is stored in a key-sequenced file.

There is always a one-to-one correspondence between index rows and base table

rows.

SQL/MP Indexes

Each row in an SQL/MP index contains:

•

A keytag column

•

The columns specified in the CREATE INDEX statement

•

The primary key of the underlying table (the user-defined primary key, the

SYSKEY, or a combination of the user-defined clustering key and the SYSKEY)

See Index Keys in the SQL/MP Reference Manual.

SQL/MX Indexes

Each row in an SQL/MX index contains:

•

The columns specified in the CREATE INDEX statement

•

The clustering key of the underlying table (the user-defined clustering key, the

SYSKEY, or a combination of the user-defined clustering key and the SYSKEY)

An index name is an SQL identifier. Indexes have their own namespace within a

schema, so an index name might be the same as a table or constraint name. However,

no two indexes in a schema can have the same name.

See CREATE INDEX Statement on page 2-52 and ALTER INDEX Statement on

page 2-7.