How do I ALTER a PostgreSQL table and make a column unique?

How do I ALTER a PostgreSQL table and make a column unique?

sql postgresql unique-constraint

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Can I add a UNIQUE constraint to a PostgreSQL table, after it's already created?

sql database postgresql indexing unique-constraint

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ERROR: there is no unique constraint matching given keys for referenced table "bar"

sql postgresql foreign-keys unique-constraint

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Naming convention for unique constraint

sql sql-server naming-conventions unique-constraint

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How can I create a unique constraint on my column (SQL Server 2008 R2)?

sql sql-server sql-server-2008 unique-constraint

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How to delete duplicate entries?

sql postgresql duplicate-removal unique-constraint sql-delete

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SQL unique varchar case sensitivity question

mysql sql case-sensitive varchar unique-constraint

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Allow null in unique column

sql postgresql database-design null unique-constraint

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How to give a unique constraint to a combination of columns in Oracle?

sql oracle constraints unique-constraint composite-key

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How to get the name of a unique constraint in postgresql?

sql postgresql constraints unique-constraint

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Unique (multiple columns) and null in one column

mysql sql database unique-constraint

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Sqlite NULL and unique? [closed]

sql sqlite null unique unique-constraint

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How to drop a unique constraint from table column?

sql database sql-server-2005 unique-constraint non-clustered-index

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SQL: How to find duplicates based on two fields?

sql oracle unique unique-constraint ora-00918

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SQL Server unique constraint problem

sql sql-server visual-studio-2010 unique-constraint

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