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what is unique key?
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Answer / mapuka mueller
A unique key in sql signifies an attribute of an entity in a
table with the unique constraint, which simply implies that,
that a record(value) of that attribute can not be entered
more than once in that column (except null).
A further assignment of the primary key constraint to that
attribute (or a composite of two or more attributes(columns)
from values on the same row) makes it the unique identifier
of the record(row) in that table.
"It's sometimes hard to express what's in your mind but i
hope i tried"
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Answer / shreekumar nair
unique key will only allow unique values in that particular column ...but it allows multiple NULL values ...since null values are not equal to an another null value...
whereas in a primary key column we can't have that ...
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Answer / laya lombi
Is the key which is commonly call as password .
| Is This Answer Correct ? | 4 Yes | 14 No |
i have a table and it has constraints and i want to get "ALTER TABLE table_name ADD CONSTRAINT constraint_name constraint type" this code must be in string type please help me if you want, i can give more explainings
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