android studio sqlite foreign key references

#Android studio sqlite foreign key references how to#
#Android studio sqlite foreign key references android#
#Android studio sqlite foreign key references series#

Then on the bottom of the table we use the two SQL reserved keywords FOREIGN KEY and REFERENCES.

OR if you want to keep that match_id, then the two participant_ids in the match table are not needed. As you can see we create a familyid of type Integer ,which should be the same type of primary ley of table families. It's never good to have duplicate information in a SQL table, they could go out of sync, and constraints could become hell (when deleting). That will only duplicate the participants id from your match table.

No need for the match_id in participant table. When you do your query to select or insert, be sure to save the correct ids in your table, and that will work. There's no problem at all in having two links to the same table. + 'FOREIGN KEY(Participant2_id) REFERENCES '+ participantTableName+'(Participant_id)' + 'FOREIGN KEY(Participant1_id) REFERENCES '+ participantTableName+'(Participant_id),' + '(Match_id integer primary key autoincrement, ' ' FOREIGN KEY(match_id) REFERENCES '+ matchTableName+'(Match_id),' + 'FOREIGN KEY(player_id) REFERENCES '+ playerTableName+'(Player_id),' + To check whether your current version of SQLite supports foreign key constraints or not, you use the following command. The SQLite library must also be compiled with neither SQLITEOMITFOREIGNKEY nor SQLITEOMITTRIGGER. + '(Participant_id integer primary key autoincrement, ' + SQLite has supported foreign key constraint since version 3.6.19. + '(Match_id integer primary key autoincrement, ' + MyDB.execSQL('CREATE TABLE IF NOT EXISTS ' + FOREIGN KEY ( + STUDENTIDFK + ) REFERENCES + TABLESTUDENT + ( + STUDENTID +.

#Android studio sqlite foreign key references android#

'UserName VARCHAR, Password VARCHAR, Experience INTEGER, Rating INTEGER) ') This is a simple project of Android SQLite Relational Database. We create an insert statement, and invoke it from an.

#Android studio sqlite foreign key references series#

+ ' (Player_id integer primary key autoincrement, ' + 11K views 7 years ago Android development with Android Studio Next video in a series on saving data into multiple tables in SQLite.

#Android studio sqlite foreign key references how to#

I am trying to create the Match table so that it can reference two Match participants but I am unsure how to do this.Ĭode I have done to create tables myDB.execSQL('CREATE TABLE IF NOT EXISTS ' Then finally a Match participant table which will have an id, player_id (foreign key), match_id (foreign key) and a score which is an integer. I have a player table which contains an id, name password. Hello subscribers, this is my walk through video on sqlite database using android studio. create table createdtopicstable (CREATEDTOPICID INTEGER PRIMARY KEY AUTOINCREMENT, TOPICID INTEGER,USERID INTEGER, FOREIGN KEY (TOPICID) REFERENCES topicstable (ID),FOREIGN KEY (USERID) REFERENCES userstable (ID)) One other note on sqlite foreign keys. You can read more about the performance benefits on this blog.I am trying to store match results in a database. Database operations are defined using the SQLiteOpenHelper: public class PostsDatabaseHelper extends SQLiteOpenHelper Note: If you are inserting a large number of records, you might want to use a compiled SQLiteStatement. We need to write our own class to handle database operations such as creation, upgrading, reading and writing. A foreign key is a way to enforce referential integrity within your SQLite database. If you want to use SQLite directly but reduce the verbosity of working with the database, check out our Easier SQL with Cupboard guide for a middle ground between SQLite and a full-fledged ORM. This SQLite tutorial explains how to use Foreign Keys in SQLite with syntax and examples. In this guide, we'll use the example of building a database to persist user created 'Posts' to demonstrate SQLite and SQLiteOpenHelper. For maximum control over local data, developers can use SQLite directly by leveraging SQLiteOpenHelper for executing SQL requests and managing a local database.