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Results tagged with unique-constraint
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user 220148
DDL UNIQUE constraints ensure that the data contained in a column, or a group of columns, is unique among all the rows in the table. The data contained in the column or columns involved is, therefore, useful to uniquely identify a row in the relevant table.
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Is there a performance penalty when there are two unique indexes on a table with all of the ...
In my database I have a table with two indexes. There is one unique index #1 on columns a,b which I need for data integrity reasons. I have another index #2 with columns c,a,b that is used for perform …
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