Android Data Storage--sqlite Database

This article integrates the use of the Android database to save an entity class as an example.

First look at the database statement:

ORM: Relational Object mapping

Add Data:

new ContentValues(); values.put("name""小丽"); values.put("phone""110"); mDB.insert("student",//表名             null//规避插入语句的错误             values );//插入的值 

Delete data:

mDB.delete("student"//表名           "name =?",//条件语句           newString[]{"小丽"});//条件语句的占位符

To modify the data:

new ContentValues();  values.put("phone""10086");  mDB.update("student",//表名              //要修改的值              "name =?",//条件语句              newString[]{"小丽"});

Query data:

cursor cursor = Mdb.query ("Student",//Table name                NULL,//query fields                NULL,//Conditional statements                NULL,placeholder for the//conditional statement                NULL,//Grouping statements                NULL,//Group conditions                NULL);//SortBoolean tofirst = Cursor.movetofirst (); while(Tofirst) {StringName = Cursor.getstring (Cursor.getcolumnindex ("Name"));StringPhone = cursor.getstring (Cursor.getcolumnindex ("Phone")); MyData MyData =NewMyData (name, phone);            Datalist.add (MyData);        Tofirst = Cursor.movetonext (); }

Here are the steps to create and use a database

1. Method invocation

private DBMang_Order dbMang_Order; dbMang_Order=DBMang_Order.getInstance(getApplicationContext());//查询ArrayList<OrderUncheck> uncheckList = dbMang_Order.query();//删除dbMang_Order.delete(orderNo);//增加dbMang_Order.insert(new OrderUncheck(orderNo, account, action));//修改dbMang_Order.update(new OrderUncheck(orderNo, account, action));

2. First create the entity class to store

 Public classOrderuncheck {String OrderNo;DoubleAccountintAction PublicStringGetorderno() {returnOrderNo; } Public void Setorderno(String OrderNo) { This. OrderNo = OrderNo; } Public Double Getaccount() {returnAccount } Public void Setaccount(Doubleaccount) { This. account = account; } Public int getaction() {returnAction } Public void setaction(intAction) { This. Action = action; } Public Orderuncheck(String OrderNo,DoubleAccountintAction) {super (); This. OrderNo = OrderNo; This. account = account; This. Action = action; }}

3. Create a Database

ImportAndroid.content.Context;ImportAndroid.database.sqlite.SQLiteDatabase;ImportAndroid.database.sqlite.SQLiteOpenHelper; Public  class mysql_order extends sqliteopenhelper {     Private Static FinalString name ="Count";//Database name     Private Static Final intVersion =1;//Database version     The third parameter, cursorfactory, specifies the factory class that obtains a cursor instance when the query is executed, set to NULL, which represents the use of the system default factory class     Public Mysql_order(Context context) {Super(Context, Name,NULL, version); }@Override     Public void onCreate(Sqlitedatabase db) {String sql="CREATE TABLE neworder (_id INTEGER PRIMARY KEY autoincrement,orderno varchar ($), account VARCHAR (19100), action VARCHAR) ";    Db.execsql (SQL); }@Override     Public void Onupgrade(Sqlitedatabase DB,intOldversion,intNewVersion) {//TODO auto-generated method stub}}

4, the code is called in the method in this class: adding and deleting changes

 Public classDbmang_order {Private StaticDbmang_order mdbmanager=NewDbmang_order ();Private StaticSqlitedatabase mDb;Private StaticContext context;Private  Dbmang_order() {    } Public StaticSynchronized Dbmang_ordergetinstance(Context context) {Dbmang_order.context = context;if(mdb==NULL) {Mysql_order MySQL =NewMysql_order (context);        MDb = Mysql.getwritabledatabase (); }returnMdbmanager; }Interfacenewtable{String table_name="Neworder"; String table_column_orderno="OrderNo"; String table_column_account="Account"; String table_column_action="Action"; }//Increase     Public void Insert(Orderuncheck info) {Contentvalues values=NewContentvalues ();        Values.put (Newtable.table_column_orderno, Info.getorderno ());        Values.put (Newtable.table_column_account, Info.getaccount ());        Values.put (Newtable.table_column_action, Info.getaction ()); LOG.W ("Mdb.insert",""+info); LOG.W ("Mdb.insert",""+ values); Mdb.insert (Newtable.table_name,NULL, values); }//Delete     Public void Delete(String OrderNo) {LOG.W ("Delete", OrderNo); Mdb.delete (Newtable.table_name, newtable.table_column_orderno+"=?",NewString[]{orderno}); }//Change     Public void Update(Orderuncheck info) {Contentvalues values =NewContentvalues ();        Values.put (Newtable.table_column_account, Info.getaccount ()); Mdb.update (Newtable.table_name, values, newtable.table_column_orderno+"=? and "+newtable.table_column_orderno+"=?",NewString[]{string.valueof (Info.getorderno ()),""+info.getaccount ()}); }//Check     PublicArraylist<orderuncheck>Query() {Cursor cursor = Mdb.query (Newtable.table_name,NULL,NULL,NULL,NULL,NULL,NULL); Arraylist<orderuncheck> list=NewArraylist<orderuncheck> (); Boolean tofirst = Cursor.movetofirst (); while(Tofirst) {String OrderNo = cursor.getstring (Cursor.getcolumnindex (Newtable.table_column_orderno)            );            String account = cursor.getstring (Cursor.getcolumnindex (Newtable.table_column_account)); String action = cursor.getstring (Cursor.getcolumnindex (Newtable.table_column_account));DoubleAccountd = double.parsedouble (account);intActiond=integer.parseint (action); Orderuncheck order =NewOrderuncheck (OrderNo, Accountd,actiond);            List.add (order);        Tofirst=cursor.movetonext (); } cursor.close ();returnList }       }

Android Data Storage--sqlite Database