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

Depending on which version of SQLite your app is running on, you might be able to use SQLite's foreign key support.

In older version's of SQLite you might be able to use the genfkey utility to create triggers to enforce your foreign key constraints (older versions of SQLite would parse foreign key constraints added during a CREATE TABLE statement, but wouldn't actually implement them).

Hope this helps.

Answer 2

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.

Answer 3

Simple start for you

create trigger simple_trigger1 after insert on database_patient_table begin update database_notes_table; end 
create trigger simple_trigger2 after delete on database_patient_table begin update database_notes_table; end

Use this documentation http://www.sqlite.org/lang_createtrigger.html