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To allow naming of a PRIMARY KEY constraint, and for defining a PRIMARY KEY constraint on multiple columns, use the following SQL syntax: MySQL / SQL Server / Oracle / MS Access: CREATE TABLE Persons ( ID int NOT NULL, LastName varchar (255) NOT NULL, FirstName varchar (255), Age int, CONSTRAINT PK_Person PRIMARY KEY (ID,LastName) );
This tutorial shows you how to use Oracle PRIMARY KEY constraint to create, add, disable, enable, and drop a primary key of a table.
28 Αυγ 2015 · To add a primary key constraint to an existing column use the form: ALTER TABLE `goods` MODIFY COLUMN `id` INT(10) UNSIGNED PRIMARY KEY AUTO_INCREMENT; NOTE: Apparently with some versions of MYSQL you must replace MODIFY with CHANGE (Thanks @csr-nontol !)
To create a new table with a column defined as the primary key, you can use the keyword PRIMARY KEY at the end of the definition of that column. In our example, we create the table product using a CREATE TABLE clause, with the names of the columns and their respective data types in parentheses.
21 Ιουλ 2010 · In MySQL, the name of a PRIMARY KEY is PRIMARY. CREATE TABLE IF NOT EXISTS `default_test` ( `default_test`.`id` SMALLINT NOT NULL AUTO_INCREMENT, `default_test`.`name` LONGTEXT NOT NULL, PRIMARY KEY (`id`) )
CREATE TABLE table_name( column1 datatype, column2 datatype, column3 datatype, ..., PRIMARY KEY(column1, column2) ); In this syntax, you list the primary key columns inside parentheses, separated by commas, followed by the PRIMARY KEY keywords.
The syntax for creating a primary key with the CREATE TABLE option is as follows. CREATE TABLE table_name ( column1 datatype PRIMARY KEY, column2 datatype [ NULL | NOT NULL ], ... ); If you are creating a primary key on more than one column, use the below syntax.
