A brief discussion on SQLite database

1. Writing class inheritance Sqlithelper;

 Public class extends Sqliteopenhelper {}

2. Implement its constructor;

     Public Sqlitehelper (Context context) {        thisnull, db_version);    }          Public Sqlitehelper (Context context, String name, Cursorfactory factory,            int  version) {         Super (context, TABLE_NAME, factory, db_version);        }

3. Define the database name, table name, version, and all columns of the table

    Private Static FinalString db_name = "Playerdatas";//Database name    Private Static FinalString table_name = "datas";//Table name    Private Static Final intDb_version = 1;//Database Version//column name of the table    Private Static FinalString table_id = "_id"; Private Static FinalString table_videoid = "VideoID"; Private Static FinalString Table_url = "URL"; Private Static FinalString table_title = "TITLE"; Private Static FinalString table_content = "CONTENT"; Private Static FinalString table_actors = "ACTORS"; Private Static FinalString table_director = "DIRECTOR"; Private Static FinalString table_type = "TYPE"; Private Static FinalString Table_icon = "ICON";

4. Implement the OnCreate method, write the SQL statement, create the table

@Override Public voidonCreate (Sqlitedatabase db) { This. db =DB; StringBuilder Builder=NewStringBuilder (); Builder.append ("CREATE table if not exists");        Builder.append (table_name); Builder.append ("("); Builder.append (table_id). Append ("Integer primary key AutoIncrement,"); Builder.append (table_videoid). Append ("Integer,"); Builder.append (Table_icon). Append ("Integer,"); Builder.append (Table_url). Append ("varchar (50),"); Builder.append (Table_title). Append ("varchar (30),"); Builder.append (table_content). Append ("varchar (50)"); Builder.append (" ) ");    Db.execsql (Builder.tostring ()); }

5 Implement the Onupgrade method, which is called when the version is upgraded

    /**      * Version update     * /     @Overridepublicvoidint int newversion) {        Db.execsql ("DROP TABLE IF EXISTS" + table_name);        OnCreate (db);    }

6. Write query, delete, update and other operation methods.

/*** Query all data *@return     */     PublicCursor Query () {Sqlitedatabase db=getreadabledatabase (); //Get CorsorCursor C = db.query (table_name,NULL,NULL,NULL,NULL,NULL,NULL); returnC; }    /*** Find data by ID *@paramID *@return     */     PublicCursor Querybyid (intvideoid) {Sqlitedatabase db=getreadabledatabase (); Cursor C= Db.query (table_name,NewString[]{table_videoid}, "Videoid=?",                 NewString[]{string.valueof (VideoID)},NULL,NULL,NULL); returnC; }        /*** Delete data based on unique identification _id *@paramID*/     Public voidDeleteintID) {Sqlitedatabase db=getwritabledatabase (); System.out.println (">>>>>>>>>>>>>>>>>>>>>>>>>>" +db); Db.delete (table_name,"_id=?",Newstring[]{string.valueof (ID)}); }    /*** Insert Method *@paramValues Insert Value*/     Public voidInsert (Contentvalues values) {Sqlitedatabase db=getwritabledatabase (); Db.insert (table_name,NULL, values);    Db.close (); }

7. How to close the database

    /**      * Close Database     * /public     void  close ()        {if  null) {            db.close ();        }    }

A brief discussion on SQLite database