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      • We want to modify this table and add a UNIQUE constraint to column name. This is possible by using the ALTER TABLE clause. First we write ALTER TABLE, then we list the name of the table (in our example: product), and next we add the clause ADD CONSTRAINT with the name of the UNIQUE constraint (in our example: UQ_product_name).
      learnsql.com/cookbook/how-to-make-a-column-unique-in-sql/

      How to Make a Column Unique in SQL? - LearnSQL.com

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  3. www.w3schools.com › sqL › sql_uniqueSQL UNIQUE Constraint - W3Schools

    Learn how to create, name and drop a UNIQUE constraint on a column or multiple columns in SQL Server, Oracle, MS Access and MySQL. A UNIQUE constraint ensures that all values in a column are different.

  4. learnsql.com › how-to-make-a-column-unique-in-sqlHow to Make a Column Unique in SQL? - LearnSQL.com

    Learn how to create or modify a table with a UNIQUE constraint on one or more columns using SQL commands. See examples for PostgreSQL, Oracle, MySQL and MS SQL Server databases.

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  6. learn.microsoft.com › en-us › sqlCreate unique constraints - SQL Server | Microsoft Learn

    Dec 20, 2023 · Learn how to create a unique constraint in SQL Server to ensure no duplicate values in specific columns that don't participate in a primary key. See examples using SSMS and Transact-SQL for different scenarios.

  7. stackoverflow.com › questions › 3734891How to use ALTER TABLE to add a new column and make it unique?

    Sep 17, 2010 · ALTER TABLE table_name ADD column_name datatype ALTER TABLE table_name ADD UNIQUE (column_name) If you want to give a name to the UNIQUE constraint, you could replace the last command with this: ALTER TABLE table_name ADD CONSTRAINT constraint_name UNIQUE (column_name)

  8. www.sqlservertutorial.net › sql-server-basics › sqlAn Essential Guide to SQL Server UNIQUE Constraint

    SQL Server UNIQUE constraints allow you to ensure that the data stored in a column, or a group of columns, is unique among the rows in a table. The following statement creates a table whose data in the email column is unique among the rows in the hr.persons table:

  9. www.sqlservertutorial.net › sql-server-basics › sqlSQL Server ALTER TABLE ALTER COLUMN - SQL Server Tutorial

    SQL Server allows you to perform the following changes to an existing column of a table: Modify the data type. Change the size. Add a NOT NULL constraint. Modify column’s data type. To modify the data type of a column, you use the following statement: ALTER TABLE table_name . ALTER COLUMN column_name new_data_type(size);

  10. www.sqlservertutorial.org › sql-server-uniqueSQL Server UNIQUE CONSTRAINT

    SQL Server UNIQUE CONSTRAINT. The objective of this SQL Server tutorial is to teach you how to use the UNIQUE CONSTRAINT to ensure the uniqueness of data in one or more columns in a table.