Head Fisrt Android Development读书笔记(7)Database Persistent

Creating the database

Create a new class called TimeTrackerOpenHelper that extends SQLiteOpenHelper. Pass the database name and the database version to super.

TimeTrackerOpenHelper(Context context)

 super(context, "timetracker.db", null, 1)

// timetracker.db is the db name, 1 is version

public void onCreate(SQLiteDatabase database) {

 database.execSQL(

 "create table timerecords " +

 "(id integer primary key, time text, notes text)");

);

}

public void onUpgrade(SQLiteDatabase database) {

 database.execSQL("DROP TABLE IF EXISTS timerecords");

 onCreate(database);

}

instead of using execSQL, we can use ContentValues

ContentValues contentValues = new ContentValues();

contentValues.put(COLUMN_NAME, VALUE);

database.insert(TABLE_NAME, null, contentValues);

query the database

sqlite queries return cursors

public Cursor getAllTimeRecords() {

 return database.rawQuery(

 "select * from " + TABLE_NAME, null

);

}

public class TimeTrackerAdapter extends CursorAdapter {

 public TimeTrackerAdapter(Context context, Cursor cursor) {

  super(content, cursor);

 }

}

原文地址:https://www.cnblogs.com/java20130722/p/3206861.html