How to use TRIGGER in Android SQLite

Question

I have two tables in database:

• table one has name and room number column
• table two has room number and time column.

Now when the r

Answer 1

Demo for Sqlite Trigger in Android HERE

Trigger are some procedural code executed after certain event occur in our database.

I have wrote a sample demo for trigger.

Example: Consider a database of any University. So if any Student record is added in student table , new row(tuple) is added automatically in library section or canteen section etc.

So by writing a simple trigger we can automatically insert new records in other sections avoiding boiler plate code.

Schema

 CREATE TABLE student (sid INTEGER PRIMARY KEY, sname TEXT)  
 CREATE TABLE canteen (cid , sid )  
 CREATE TABLE library (lid INTEGER PRIMARY KEY, sid TEXT)

Trigger to automatically add records in library and canteen table:

CREATE TRIGGER if not exists add_student   
   AFTER INSERT  
 ON[student]  
   for each row  
     BEGIN  
        insert into library values (2 , new.sid );  
        insert into canteen values (3 , new.sid);  
     END; 

Explanation:The concept here is to create a trigger ,which insert the values in canteen and library based on new student id.