child tables for a give parent table
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Thread: child tables for a give parent table

  1. #1
    Join Date
    Jan 2001
    Posts
    157

    Smile

    What does this RDBMS jargon mean
    "Child Tables for a given parent table". Can any body explain this in plain english to me?

  2. #2
    Join Date
    Jun 2000
    Location
    Madrid, Spain
    Posts
    7,448
    child table are those tables that references a parent table

    for example table emp and table dept

    dept would be the parent table and emp the child

    emp would have a foreign key that references dept primary key

    the values in foreign key column in emp must be null (depends on how´s ur relationship) or one of PK in dept

    does this help...?

  3. #3
    Join Date
    Jan 2001
    Posts
    157
    thanks Pando. The explanation is perfect.

  4. #4
    Join Date
    May 2000
    Location
    ATLANTA, GA, USA
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    3,136
    When a relationship is made between entities, there are 3 types; 1 Identifying 2 Non-identifying 3 Non-Specific.

    The 2nd major category is "existence". There are 2; one is "mandatory" and the other is "Optional".

    When you say Identifying and Mandatory then the attribute will become part of the primary key in the child table, otherwise it will not become part of PK.

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