Android Open Source - watchme Database Helper

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Back to project page watchme.

License

The source code is released under:

Copyright (c) 2012 Johan Brook, Robin Andersson, Lisa Stenberg, Mattias Henriksson Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documen...

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Java Source Code

/**
 *  DatabaseHelper.java// w  w w .  j av a 2 s.c o  m
 *
 *  Manage Database creation and version managements. 
 *
 *  @author lisastenberg
 *  @copyright (c) 2012 Johan Brook, Robin Andersson, Lisa Stenberg, Mattias Henriksson
 *  @license MIT
 */

package se.chalmers.watchme.database;

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;

public class DatabaseHelper extends SQLiteOpenHelper {

  private static final int DATABASE_VERSION = 1;
  private static final String DATABASE_NAME = "watchme.db";

  private static final String TRIGGER_DETACH = "detach";
  private static final String TRIGGER_DETACH2 = "detach2";

  /**
   * When a Movie is deleted, the rows in the HasTag-table containing that
   * Movie should also be deleted.
   */
  private static final String CREATE_TRIGGER_DETACH = "CREATE TRIGGER "
      + TRIGGER_DETACH + " AFTER " + "DELETE ON "
      + MoviesTable.TABLE_MOVIES + " FOR EACH ROW BEGIN "
      + "DELETE FROM " + HasTagTable.TABLE_HAS_TAG + " WHERE "
      + HasTagTable.COLUMN_MOVIE_ID + " = old."
      + MoviesTable.COLUMN_MOVIE_ID + "; END;";

  /**
   * When a Tag is deleted, the rows in the HasTag-table containing that Tag
   * should also be deleted.
   */
  private static final String CREATE_TRIGGER_DETACH2 = "CREATE TRIGGER "
      + TRIGGER_DETACH2 + " AFTER " + "DELETE ON " + TagsTable.TABLE_TAGS
      + " FOR EACH ROW BEGIN " + "DELETE FROM "
      + HasTagTable.TABLE_HAS_TAG + " WHERE " + HasTagTable.COLUMN_TAG_ID
      + " = old." + TagsTable.COLUMN_TAG_ID + "; END;";

  public DatabaseHelper(Context context) {
    super(context, DATABASE_NAME, null, DATABASE_VERSION);
  }

  @Override
  public void onCreate(SQLiteDatabase db) {
    MoviesTable.onCreate(db);
    TagsTable.onCreate(db);
    HasTagTable.onCreate(db);

    db.execSQL(CREATE_TRIGGER_DETACH);
    db.execSQL(CREATE_TRIGGER_DETACH2);
  }

  @Override
  public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    MoviesTable.onUpgrade(db, oldVersion, newVersion);
    TagsTable.onUpgrade(db, oldVersion, newVersion);
    HasTagTable.onUpgrade(db, oldVersion, newVersion);

    db.execSQL("DROP TRIGGER IF EXISTS " + TRIGGER_DETACH);
    db.execSQL("DROP TRIGGER IF EXISTS " + TRIGGER_DETACH2);
    db.execSQL(CREATE_TRIGGER_DETACH);
    db.execSQL(CREATE_TRIGGER_DETACH2);
  }
}

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