>Hi All,
>
>Anybody can tell me the differences and its uses of index type primary, unique, candidate and regular?
>
>TIA
>
>Mike
Regular is the one you will use most commonly.
Primary and candidate will check for uniqueness. The expression you use for the index is not allowed to repeat for different records. Both basically do the same thing; primary is supposed to specify the main way of accessing the record, that is, the primary key.
Unique is for backward-compatibility, IMO. I don't see any use for it nowadays.
If you don't want to check for uniqueness, just create a regular index.
Indices can be used to show data in a certain order, but also for quick access to the data.
Indices are required if you want to define referential integrity.
HTH,
Hilmar.
Difference in opinions hath cost many millions of lives: for instance, whether flesh be bread, or bread be flesh; whether whistling be a vice or a virtue; whether it be better to kiss a post, or throw it into the fire... (from Gulliver's Travels)
