Drop Constraint From the MySQL Table Query to execute the DROP constraint in MySQL: Alter table studentPK drop primary key; The above syntax changes the syntax of studentPk using the Alter keyword. Since the constraint is at table level, it is easy to drop at table level well. The Alter...
How to drop unique constraint 28752 Sultana Jahan Rini February 17, 2006 10:33PM Re: How to drop unique constraint 48078 Roland Bouman February 18, 2006 01:25PM Sorry, you can't reply to this topic. It has been closed. This forum is currently read only. You can not log in or make...
I created a DB2 table with "UNIQUE (columnX, columnY)" in the table definition, but i now want to drop it with help of alter table, but i could not find out the name of this unique constraint with which i can drop it ("alter table drop unique" does not work...
PostgreSQL uses the ALTER TABLE command with the DROP CONSTRAINT clause to remove/drop the uniqueness from single or multiple columns: ALTERTABLEname_of_tableDROPCONSTRAINTname_of_constraint; Replace the “name_of_table” with the desired table name and “name_of_constraint” with...
Example: How Do I Drop a NOT NULL Constraint From a Postgres Table? We will use the ALTER TABLE command to remove the NOT NULL constraint from the "last_name" column: ALTER TABLE student_information ALTER COLUMN last_name DROP NOT NULL; ...
However, using the shortcut method will cause Access to randomly generate a name for the constraint, which will make it difficult to reference in code. It is a good idea always to name your constraints.To drop a constraint, use the DROP CONSTRAINT clause with the ALTER TABLE statement, and...
use and drop constraints // // SQL Statements USED: // CREATE TABLE //DROPTABLE // DELETE // COMMIT // ROLLBACK // INSERT // ALTER // // JAVA 2 CLASSES USED: // Statement // ResultSet // // Classes used fromUtil.javaare: // Db // JdbcException // // // Output will vary...
print " DROP TABLE\n"; print "TO SHOW A 'UNIQUE' CONSTRAINT.\n"; # create table print "\n CREATE TABLE empl_sal(lastname VARCHAR(10) NOT NULL,\n". " firstname VARCHAR(10) NOT NULL,\n". " salary DECIMAL(7, 2),\n". " CONSTRAINT unique_cn UNIQUE(lastname, firstname))\n";...
So while old and new unique constraints can co-exist, you must first drop the current primary key if you want to create a new one. The unique index for the new constraint means you can prevent duplicates during this process. To drop a primary key you also have to remove any foreign key...
Can anyone help me to drop a unique constriant from an existing table. I have tried " Alter table table_name drop constraint constraint_name;" But failed. With regards Rini Subject Views Written By Posted How to drop unique constraint ...