Android学习之SQLite创建表和增删改

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　　MySQLiteDemo.java:

import android.app.Activity;
import android.database.sqlite.SQLiteOpenHelper;
import android.os.Bundle;
public class MySQLiteDemo extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);// 父类onCreate()
super.setContentView(R.layout.main);// 默认布局管理器
SQLiteOpenHelper helper = new MyDatabaseHelper(this) ;// 定义数据库辅助类
helper.getWritableDatabase() ;// 以修改方式打开数据库
}
}
　　MyDatabaseHelper.java:

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
public class MyDatabaseHelper extends SQLiteOpenHelper {// 继承SQLiteOpenHelper类
private static final String DATABASENAME = "test.db" ;// 数据库名称
private static final int DATABASEVERSION = 1 ;// 数据库版本
private static final String TABLENAME = "mytab" ;// 数据表名称
public MyDatabaseHelper(Context context) {// 定义构造
super(context, DATABASENAME, null, DATABASEVERSION);// 调用父类构造
}

@Override
public void onCreate(SQLiteDatabase db) {// 创建数据表
String sql = "CREATE TABLE " + TABLENAME + " (" +
"idINTEGER PRIMARY KEY ," +
"nameVARCHAR(50)NOT NULL ," +
"birthdayDATENOT NULL)";// SQL语句
db.execSQL(sql) ;// 执行SQL语句
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
String sql = "DROP TABLE IF EXISTS " + TABLENAME ;// SQL语句
db.execSQL(sql);// 执行SQL语句
this.onCreate(db); // 创建表
}
}

　　增删改操作：
　　MySQLiteDemo.java:

import android.app.Activity;
import android.database.sqlite.SQLiteOpenHelper;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
public class MySQLiteDemo extends Activity {
private SQLiteOpenHelper helper = null ;// 数据库操作
private MytabOperate mtab = null ;// mytab表操作类
private Button insertBut = null ;// 定义按钮
private Button updateBut = null ;// 定义按钮
private Button deleteBut = null ;// 定义按钮
private static int count = 0 ;// 计数统计
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);// 父类onCreate()
super.setContentView(R.layout.main);// 默认布局管理器
this.insertBut = (Button) super.findViewById(R.id.insertBut) ;// 取得组件
this.deleteBut = (Button) super.findViewById(R.id.deleteBut) ;// 取得组件
this.updateBut = (Button) super.findViewById(R.id.updateBut) ;// 取得组件
this.helper = new MyDatabaseHelper(this) ;// 定义数据库辅助类
this.insertBut.setOnClickListener(new InsertOnClickListenerImpl()) ;// 设置监听
this.deleteBut.setOnClickListener(new DeleteOnClickListenerImpl()) ;// 设置监听
this.updateBut.setOnClickListener(new UpdateOnClickListenerImpl()) ;// 设置监听
}
private class InsertOnClickListenerImpl implements OnClickListener {
@Override
public void onClick(View view) {
MySQLiteDemo.this.mtab = new MytabOperate(
MySQLiteDemo.this.helper.getWritableDatabase()); // 取得可更新的数据库操作
MySQLiteDemo.this.mtab.insert("张三" + count ++ , "1979-08-12") ;// 增加数据
}
}
private class DeleteOnClickListenerImpl implements OnClickListener {
@Override
public void onClick(View view) {
MySQLiteDemo.this.mtab = new MytabOperate(
MySQLiteDemo.this.helper.getWritableDatabase()); // 取得可更新的数据库操作
MySQLiteDemo.this.mtab.delete(3) ;// 删除数据
}
}
private class UpdateOnClickListenerImpl implements OnClickListener {
@Override
public void onClick(View view) {
MySQLiteDemo.this.mtab = new MytabOperate(
MySQLiteDemo.this.helper.getWritableDatabase()); // 取得可更新的数据库操作
MySQLiteDemo.this.mtab.update(1, "test哈哈", "1981-06-27") ;// 更新已有数据
}
}
}
　　MytabOperate.java:

import android.database.sqlite.SQLiteDatabase;
public class MytabOperate {
private static final String TABLENAME = "mytab" ;// 表名称
private SQLiteDatabase db = null ;// SQLiteDatabase
public MytabOperate(SQLiteDatabase db) {// 构造方法
this.db = db ;
}
public void insert(String name, String birthday) {
String sql = "INSERT INTO " + TABLENAME + " (name,birthday) VALUES ('"
+ name + "','" + birthday + "')"; // SQL语句
this.db.execSQL(sql);// 执行SQL语句
this.db.close() ;// 关闭数据库操作
}
public void update(int id, String name, String birthday) {
String sql = "UPDATE " + TABLENAME + " SET name='" + name
+ "',birthday='" + birthday + "' WHERE id=" + id; // SQL语句
this.db.execSQL(sql); // 执行SQL语句
this.db.close() ;// 关闭数据库操作
}
public void delete(int id) {
String sql = "DELETE FROM " + TABLENAME + " WHERE id=" + id;// SQL语句
this.db.execSQL(sql) ;// 执行SQL语句
this.db.close() ;// 关闭数据库操作
}
}