Check constraint in mysql

    alter constraint in mysql
    modify constraint in mysql
    alter unique constraint in mysql
    alter add constraint in mysql
  • Alter constraint in mysql

    • Mysql constraint foreign key.

    15.1.9 ALTER TABLE Statement

    changes the structure of a table. For example, you can add or delete columns, create or destroy indexes, change the type of existing columns, or rename columns or the table itself.

    Mysql alter table add multiple columns

    You can also change characteristics such as the storage engine used for the table or the table comment.

    • To use , you need , , and privileges for the table. Renaming a table requires and on the old table, , , and on the new table.

    • Following the table name, specify the alterations to be made. If none are given, does nothing.

    • The syntax for many of the permissible alterations is similar to clauses of the statement.

      Mysql constraints

    • Alter table mysql rename column
    • Mysql constraint foreign key
    • Alter table add column mysql
    • Alter table modify column mysql

      • clauses use the same syntax for and as for . For more information, see Section 15.1.20, “CREATE TABLE Statement”.

    • The word is optional and can be omitted, except for (to distinguish a column-renaming operation from the table-renaming operation).

    • Multiple , , , and clauses are permitted in a single statement, separated by commas. This is a MySQL extension to standard SQL, which permits only one of each clause per statement. For example,

        alter check constraint in mysql
        alter foreign key constraint in mysql