Primary key operations
This topic describes how to add, modify, and drop primary keys in seekdb.
Add a primary key
The syntax is as follows:
ALTER TABLE table_name ADD PRIMARY KEY (column_name);
In this syntax, table_name specifies the name of the table to which you want to add a primary key, and column_name specifies the column to which you want to add the primary key. For more information, see ALTER TABLE.
Assume that a table named tbl1 exists in the database. You can add a primary key index to the tbl1 table and apply it to the c1 column. Example:
ALTER TABLE tbl1 ADD PRIMARY KEY(c1);
Modify a primary key
The syntax is as follows:
ALTER TABLE table_name DROP PRIMARY KEY, ADD PRIMARY KEY (column_name);
In this syntax, table_name specifies the name of the table to which you want to add a primary key, and column_name specifies the column to which you want to add the primary key. For more information, see ALTER TABLE.
Assume that a table named tbl1 exists in the database and that a primary key exists in the tbl1 table. You can modify the primary key in the tbl1 table and apply it to the c2 column. Example:
ALTER TABLE tbl1 DROP PRIMARY KEY, ADD PRIMARY KEY(c2);
Drop a primary key
The syntax is as follows:
ALTER TABLE table_name DROP PRIMARY KEY;
In this syntax, table_name specifies the name of the table to which you want to add a primary key. For more information, see ALTER TABLE.
Assume that a table named tbl1 exists in the database and that a primary key exists in the tbl1 table. You can drop the primary key in the tbl1 table. Example:
ALTER TABLE tbl1 DROP PRIMARY KEY;