-- SQLite TRIGGERS


CREATE TABLE EMPLOYEE ( 
  empId INTEGER PRIMARY KEY,
  name TEXT NOT NULL,
  dept TEXT NOT NULL
);


CREATE TABLE AUDIT(
   EMP_ID INTEGER NOT NULL,
   ENTRY_DATE TEXT NOT NULL
);


-- After Insert Trigger
CREATE TRIGGER a_insert AFTER INSERT 
ON EMPLOYEE 
BEGIN
   INSERT INTO AUDIT(EMP_ID, ENTRY_DATE) VALUES (NEW.empId, datetime('now'));
END;



INSERT INTO EMPLOYEE VALUES (0001, 'Clark', 'Sales');
INSERT INTO EMPLOYEE VALUES (0002, 'Dave', 'Accounting');
INSERT INTO EMPLOYEE VALUES (0003, 'Ava', 'Sales');

SELECT * FROM EMPLOYEE;

SELECT * FROM AUDIT;





-- Sqlite Trigger AFTER UPDATE 


CREATE TRIGGER a_update AFTER UPDATE   
ON EMPLOYEE 
BEGIN  
INSERT INTO AUDIT(EMP_ID, ENTRY_DATE) VALUES (new.empId, datetime('now'));  
END;  


UPDATE EMPLOYEE SET name = 'kathy' WHERE empId = 0002;


SELECT * FROM EMPLOYEE;


SELECT * FROM AUDIT;






-- SQLite TRIGGER AFTER DELETE 


CREATE TRIGGER a_delete AFTER DELETE on EMPLOYEE 

BEGIN

INSERT into AUDIT 

(EMP_ID,ENTRY_DATE)

VALUES(OLD.empId,'DELETE ' || date('now'));

END;




DELETE FROM EMPLOYEE WHERE empId = 0002; 


SELECT * FROM EMPLOYEE;


SELECT * FROM AUDIT;




-- Check for triggers
SELECT name FROM sqlite_master  
WHERE type = 'trigger';
by

SQLite online editor

Write, Run & Share SQLite queries online using OneCompiler's SQLite online editor and compiler for free. It's one of the robust, feature-rich online editor and compiler for SQLite. Getting started with the OneCompiler's SQLite editor is really simple and pretty fast. The editor shows sample boilerplate code when you choose language as 'SQLite' and start writing queries to learn and test online without worrying about tedious process of installation.

About SQLite

SQLite is an in-process C library that implements small, fast, serverless, zero-configuration, transactional SQL database engine.

Key Features:

  • Very small and light weight
  • Serverless
  • Free to use
  • Self contained as no other dependencies required.
  • zero config

Syntax help

Useful Commands

1. CREATE

CREATE TABLE table_name (
                column1 datatype,
                column2 datatype,
                ....);

Example

CREATE TABLE EMPLOYEE (
  empId INTEGER PRIMARY KEY,
  name TEXT NOT NULL,
  dept TEXT NOT NULL
);

2. ALTER

ALTER TABLE Table_name ADD column_name datatype;

Example

INSERT INTO EMPLOYEE VALUES (0001, 'Dave', 'Sales');

3. DROP

DROP TABLE table_name;

4. INSERT

INSERT INTO table_name (column1, column2, column3, ...) VALUES (value1, value2, value3, ...);

Note: Column names are optional.

Example

INSERT INTO EMPLOYEE VALUES (0001, 'Ava', 'Sales');

5. SELECT

SELECT column1, column2, ...
FROM table_name
[where condition];

Example

SELECT * FROM EMPLOYEE where dept ='sales';

6. UPDATE

UPDATE table_name
SET column1 = value1, column2 = value2, ...
WHERE condition;

Example

UPDATE EMPLOYEE SET dept = 'Sales' WHERE empId='0001';

7. DELETE

DELETE FROM table_name where condition;

Example

DELETE from EMPLOYEE where empId='0001';

8. CREATE INDEX

  CREATE [UNIQUE] INDEX index_name on table_name(column_name);

9. DROP INDEX

DROP INDEX index_name ON table_name;

10. Create a View

CREATE VIEW View_name AS 
Query;

11. How to call view

SELECT * FROM View_name;

12. Altering a View

ALTER View View_name AS 
Query;

13. Deleting a View

DROP VIEW View_name;

14. INNER JOIN

SELECT * FROM TABLE1 INNER JOIN TABLE2 where condition;

15. LEFT JOIN

SELECT * FROM TABLE1 LEFT JOIN TABLE2 ON condition;

16. RIGHT JOIN

SELECT * FROM TABLE1 RIGHT JOIN TABLE2 ON condition;

17. CROSS JOIN

SELECT select_list from TABLE1 CROSS JOIN TABLE2;