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Annotation of 42BSD/ingres/doc/quel/index.nr, revision 1.1

1.1     ! root        1: .th INDEX QUEL 2/21/79
        !             2: .sh NAME
        !             3: index \- create a secondary index on an existing relation.
        !             4: .sh SYNOPSIS
        !             5: .bd "index on"
        !             6: relname 
        !             7: .bd is
        !             8: indexname 
        !             9: (domain\c
        !            10: .it 1 
        !            11: { ,domain\c
        !            12: .it 2\c
        !            13: })
        !            14: .sh DESCRIPTION
        !            15: .it Index
        !            16: is used to create secondary indices on existing relations
        !            17: in order to make retrieval and update with secondary keys more
        !            18: efficient.
        !            19: The secondary key is constructed from relname domains 1, 2,...,6
        !            20: in the order given.
        !            21: Only the owner of a relation is allowed to
        !            22: create secondary indices on that relation.
        !            23: .s3
        !            24: In order to maintain the integrity of the index, users will NOT
        !            25: be allowed to directly update
        !            26: secondary indices. 
        !            27: However, whenever a primary relation is changed,
        !            28: its secondary indices will be automatically updated by the system.
        !            29: Secondary indices may be modified to further increase the access
        !            30: efficiency of the primary relation.
        !            31: When an index is first created, it is automatically
        !            32: modified to an isam storage structure
        !            33: on all its domains.
        !            34: If this structure is undesirable, the user may override
        !            35: the default isam structure by using the
        !            36: .bd \-n
        !            37: switch (see ingres(unix)), or by entering
        !            38: a 
        !            39: .it modify
        !            40: command directly.
        !            41: .s3
        !            42: If a 
        !            43: .it modify 
        !            44: or 
        !            45: .it destroy 
        !            46: command is used on 
        !            47: .it relname\c
        !            48: , all secondary indices on 
        !            49: .it relname 
        !            50: are destroyed.
        !            51: .s3
        !            52: Secondary indices on other indices, or on system
        !            53: relations are forbidden.
        !            54: .sh EXAMPLE
        !            55: .nf
        !            56: /\*(** Create a secondary index called ``x'' on relation ``emp'' \*(**/
        !            57:    index on emp is x(mgr,sal)
        !            58: .fi
        !            59: .sh "SEE ALSO"
        !            60: copy(quel), destroy(quel), modify(quel)
        !            61: .sh BUGS
        !            62: At most 6 domains may appear in the key.
        !            63: .s3
        !            64: The 
        !            65: .it copy 
        !            66: command cannot be used to copy into
        !            67: a relation which has secondary indices.
        !            68: .s3
        !            69: The default structure isam is a poor choice
        !            70: for an index unless the range of retrieval
        !            71: is small.

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