• Create a table
  CREATE TABLE mystaff( id NUMBER(2), fname VARCHAR2(20), lname VARCHAR2(30))
• Add an unique constraints
  • ALTER TABLE mystaff
 ADD CONSTRAINT uq1 UNIQUE (id) DISABLE
• Disable and enable the constraint
  • ALTER TABLE mystaff ENABLE CONSTRAINT uq1
• Insert data using pdo-transaction  application (custom)
  try {
  $dbh = new PDO("oci:dbname=".$tns,$db_username,$db_password);
  echo "Connected\n";
  } catch (Exception $e) {
  die("Unable to connect: " . $e->getMessage());
  }
  try {
  $dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
  $dbh->beginTransaction();
  //$dbh->exec("insert into staff (id, first, last) values (23, 'David', 'Mukherjee')");
  $dbh->exec($sql);
  $dbh->commit();
  } catch (Exception $e) {
  $dbh->rollBack();
  echo "Failed: " . $e->getMessage();
  }
   

CREATE TABLE mystaff( id NUMBER(2), fname VARCHAR2(20), lname VARCHAR2(30))

Check this empty table

ALTER TABLE mystaff ADD CONSTRAINT uq1 UNIQUE (id) DISABLE

Verifying unique constraints

ALTER TABLE mystaff ENABLE CONSTRAINT uq1

VERIFY :

SELECT TABLE_NAME, CONSTRAINT_NAME, STATUS FROM USER_CONSTRAINTS

insert into mystaff (id, fname, lname) values (10, 'Dan', 'Parker')

Verifying the above insert query

insert into mystaff (id, fname, lname) values (1001, 'Peter', 'Pan')

Now add id that would be 2 digit integer

Verify the above action.