ALTER TABLE data.transdocdtl 
	MODIFY(
	docid   VARCHAR2(14) NOT NULL,
	doctype VARCHAR2(14) NOT NULL, 
	transdt DATE         NOT NULL);

CREATE TABLE temp_drop ( a NUMBER NOT NULL);

SELECT constraint_name
  FROM user_constraints
 WHERE table_name = 'TEMP_DROP';


CONSTRAINT_NAME               
------------------------------
SYS_C00158927                 

1 row selected.

ALTER TABLE temp_drop RENAME CONSTRAINT SYS_C00158927 TO new_name;

SELECT constraint_name
  FROM user_constraints
 WHERE table_name = 'TEMP_DROP';

CONSTRAINT_NAME               
------------------------------
NEW_NAME                      

1 row selected.

SQL> CREATE TABLE temp1 (a NUMBER NOT NULL, b NUMBER NOT NULL)
Table created.
SQL> CREATE TABLE temp2 (a NUMBER NOT NULL, b NUMBER NOT NULL)
Table created.
SQL> CREATE TABLE temp3 (a NUMBER NOT NULL, b NUMBER NOT NULL)
Table created.

SQL> -- Case 1

SQL> -- Create Manual Script For DISABLE

SQL> SELECT    'ALTER TABLE '
       || table_name
       || ' DISABLE CONSTRAINT '
       || constraint_name
       || ';'
  FROM user_constraints
 WHERE table_name IN ('TEMP1', 'TEMP2', 'TEMP3')

'ALTERTABLE'||TABLE_NAME||'DISABLECONSTRAINT'||CONSTRAINT_NAME||';'             
--------------------------------------------------------------------------------
ALTER TABLE TEMP1 DISABLE CONSTRAINT SYS_C00158946;                             
ALTER TABLE TEMP1 DISABLE CONSTRAINT SYS_C00158947;                             
ALTER TABLE TEMP2 DISABLE CONSTRAINT SYS_C00158948;                             
ALTER TABLE TEMP2 DISABLE CONSTRAINT SYS_C00158949;                             
ALTER TABLE TEMP3 DISABLE CONSTRAINT SYS_C00158950;                             
ALTER TABLE TEMP3 DISABLE CONSTRAINT SYS_C00158951;                             

6 rows selected.

SQL> -- Create Manual Script For ENABLE 

SQL> SELECT    'ALTER TABLE '
       || table_name
       || ' ENABLE CONSTRAINT '
       || constraint_name
       || ';'
  FROM user_constraints
 WHERE table_name IN ('TEMP1', 'TEMP2', 'TEMP3')

'ALTERTABLE'||TABLE_NAME||'ENABLECONSTRAINT'||CONSTRAINT_NAME||';'              
--------------------------------------------------------------------------------
ALTER TABLE TEMP1 ENABLE CONSTRAINT SYS_C00158946;                              
ALTER TABLE TEMP1 ENABLE CONSTRAINT SYS_C00158947;                              
ALTER TABLE TEMP2 ENABLE CONSTRAINT SYS_C00158948;                              
ALTER TABLE TEMP2 ENABLE CONSTRAINT SYS_C00158949;                              
ALTER TABLE TEMP3 ENABLE CONSTRAINT SYS_C00158950;                              
ALTER TABLE TEMP3 ENABLE CONSTRAINT SYS_C00158951;                              

6 rows selected.

SQL> /* You can this scripts to ENABLE or DISABLE your table constraints*/

SQL> -- case 2 
SQL> -------------------------------------------------------------------------------
SQL> -- BY BLOCK to DISABLE constraints
SQL> -------------------------------------------------------------------------------

SQL> DECLARE
   l_fun   VARCHAR2 (10) := 'DISABLE';
BEGIN
   FOR i IN (SELECT table_name, constraint_name
               FROM user_constraints
              WHERE table_name IN ('TEMP1', 'TEMP2', 'TEMP3'))
   LOOP
      EXECUTE IMMEDIATE    'ALTER TABLE '
                        || i.table_name
                        || ' '
                        || l_fun
                        || ' '
                        || 'CONSTRAINT '
                        || i.constraint_name;
   END LOOP;
END;
PL/SQL procedure successfully completed.

SQL> -- Check for DISABLE constarints

SQL> SELECT table_name, constraint_name, status
  FROM user_constraints
 WHERE table_name IN ('TEMP1', 'TEMP2', 'TEMP3')

TABLE_NAME                     CONSTRAINT_NAME                STATUS  
------------------------------ ------------------------------ --------
TEMP1                          SYS_C00158946                  DISABLED
TEMP1                          SYS_C00158947                  DISABLED
TEMP2                          SYS_C00158948                  DISABLED
TEMP2                          SYS_C00158949                  DISABLED
TEMP3                          SYS_C00158950                  DISABLED
TEMP3                          SYS_C00158951                  DISABLED

6 rows selected.

SQL> ------------------------------------------------------------------------------- 
SQL> -- BY BLOCK to DISABLE constraints 
SQL> -------------------------------------------------------------------------------

SQL> DECLARE
   l_fun   VARCHAR2 (10) := 'ENABLE';
BEGIN
   FOR i IN (SELECT table_name, constraint_name
               FROM user_constraints
              WHERE table_name IN ('TEMP1', 'TEMP2', 'TEMP3'))
   LOOP
      EXECUTE IMMEDIATE    'ALTER TABLE '
                        || i.table_name
                        || ' '
                        || l_fun
                        || ' '
                        || 'CONSTRAINT '
                        || i.constraint_name;
   END LOOP;
END;
PL/SQL procedure successfully completed.

SQL> -- Check for DISABLE constarints

SQL> SELECT table_name, constraint_name, status
  FROM user_constraints
 WHERE table_name IN ('TEMP1', 'TEMP2', 'TEMP3')

TABLE_NAME                     CONSTRAINT_NAME                STATUS  
------------------------------ ------------------------------ --------
TEMP1                          SYS_C00158946                  ENABLED 
TEMP1                          SYS_C00158947                  ENABLED 
TEMP2                          SYS_C00158948                  ENABLED 
TEMP2                          SYS_C00158949                  ENABLED 
TEMP3                          SYS_C00158950                  ENABLED 
TEMP3                          SYS_C00158951                  ENABLED 

6 rows selected.

create table test_102 (col_1 number constraint test_102_nn01 not null);

--drop the constraint if it already exists 
alter table abc drop constraint abc_a_nn; 
alter table abc add constraint abc_a_nn CHECK (a IS NOT NULL);