本篇整合Android数据库的使用，以保存一个实体类为例子。

先来看下数据库语句：

ORM:关系对象映射

增加数据：

ContentValues values = 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

删除数据：

mDB.delete("student", //表名 "name =http://www.it165.net/database/html/201503/?",//条件语句 new String[]{"小丽"});//条件语句的占位符

修改数据：

ContentValues values = new ContentValues(); values.put("phone", "10086"); mDB.update("student",//表名 values, //要修改的值 "name =http://www.it165.net/database/html/201503/?",//条件语句 new String[]{"小丽"});

查询数据：

Cursor cursor = mDB.query("student",//表名 null,//查询的字段 null,//条件语句 null,//条件语句的占位符 null,//分组语句 null,//分组条件 null);//排序 boolean toFirst = cursor.moveToFirst(); while(toFirst){ String name = cursor.getString(cursor.getColumnIndex("name")); String phone = cursor.getString(cursor.getColumnIndex("phone")); MyData myData = new MyData(name, phone); dataList.add(myData); toFirst = cursor.moveToNext(); }

下面是数据库创建及使用步骤

1、方法调用

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、首先创建要存储的实体类

public class OrderUncheck { String orderNo; double account; int action; public String getOrderNo() { return orderNo; } public void setOrderNo(String orderNo) { this.orderNo = orderNo; } public double getAccount() { return account; } public void setAccount(double account) { this.account = account; } public int getAction() { return action; } public void setAction(int action) { this.action = action; } public OrderUncheck(String orderNo, double account, int action) { super(); this.orderNo = orderNo; this.account = account; this.action = action; } }

3、创建数据库

import android.content.Context; import android.database.sqlite.SQLiteDatabase; import android.database.sqlite.SQLiteOpenHelper; public class MySQL_Order extends SQLiteOpenHelper { private static final String name = "count"; //数据库名称 private static final int version = 1; //数据库版本 //第三个参数CursorFactory指定在执行查询时获得一个游标实例的工厂类,设置为null,代表使用系统默认的工厂类 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(200),account VARCHAR(19100),action VARCHAR(200))"; db.execSQL(sql); } @Override public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { // TODO Auto-generated method stub } }

4、代码中被调用的方法在这个类：增删改查

public class DBMang_Order { private static DBMang_Order mDbManager=new DBMang_Order(); private static SQLiteDatabase mDb; private static Context context; private DBMang_Order() { } public static synchronized DBMang_Order getInstance(Context context){ DBMang_Order.context = context; if(mDb==null){ MySQL_Order mySQL = new MySQL_Order(context); mDb = mySQL.getWritableDatabase(); } return mDbManager; } interface NewTable{ String TABLE_NAME="neworder"; String TABLE_COLUMN_orderNo="orderNo"; String TABLE_COLUMN_account="account"; String TABLE_COLUMN_action="action"; } //增 public void insert(OrderUncheck info){ ContentValues values=new ContentValues(); 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); } //删 public void delete(String orderNo) { Log.w("delete", orderNo); mDb.delete(NewTable.TABLE_NAME, NewTable.TABLE_COLUMN_orderNo+"=http://www.it165.net/database/html/201503/?", new String[]{orderNo}); } //改 public void update(OrderUncheck info){ ContentValues values = new ContentValues(); values.put(NewTable.TABLE_COLUMN_account, info.getAccount()); mDb.update(NewTable.TABLE_NAME, values, NewTable.TABLE_COLUMN_orderNo+"=http://www.it165.net/database/html/201503/? and "+NewTable.TABLE_COLUMN_orderNo+"=http://www.it165.net/database/html/201503/?", new String[]{String.valueOf(info.getOrderNo()),""+info.getAccount()}); } //查 public ArrayList<OrderUncheck> query(){ Cursor cursor = mDb.query(NewTable.TABLE_NAME, null, null, null, null, null, null); ArrayList<OrderUncheck> list=new ArrayList<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)); double accountd = Double.parseDouble(account); int actiond=Integer.parseInt(action); OrderUncheck order = new OrderUncheck(orderNo, accountd,actiond); list.add(order); toFirst=cursor.moveToNext(); } cursor.close(); return list; } }