Android SQLite基本用法详解

db=SQLiteDatabase.openOrCreateDatabase("/data/data/com.lingdududu.db/databases/stu.db",null);

private void createTable(SQLiteDatabase db){
//创建表SQL语句
String stu_table="create table usertable(_id integer primary key autoincrement,sname text,snumber text)";
//执行SQL语句
db.execSQL(stu_table);
}

private void insert(SQLiteDatabase db){
//实例化常量值
ContentValues cValue = new ContentValues();
//添加用户名
cValue.put("sname","xiaoming");
//添加密码
cValue.put("snumber","01005");
//调用insert()方法插入数据
db.insert("stu_table",null,cValue);
}

private void insert(SQLiteDatabase db){
//插入数据SQL语句
String stu_sql="insert into stu_table(sname,snumber) values('xiaoming','01005')";
//执行SQL语句
db.execSQL(sql);
}

private void delete(SQLiteDatabase db) {
//删除条件
String whereClause = "id=?";
//删除条件参数
String[] whereArgs = {String.valueOf(2)};
//执行删除
db.delete("stu_table",whereClause,whereArgs);
}

private void delete(SQLiteDatabase db) {  
//删除SQL语句  
String sql = "delete from stu_table where _id = 6";  
//执行SQL语句  
db.execSQL(sql);  
}  

private void update(SQLiteDatabase db) {  
//实例化内容值 ContentValues values = new ContentValues();  
//在values中添加内容  
values.put("snumber","101003");  
//修改条件  
String whereClause = "id=?";  
//修改添加参数  
String[] whereArgs={String.valuesOf(1)};  
//修改  
db.update("usertable",values,whereClause,whereArgs);  
}

private void update(SQLiteDatabase db){  
//修改SQL语句  
String sql = "update stu_table set snumber = 654321 where id = 1";  
//执行SQL  
db.execSQL(sql);  
}

private void query(SQLiteDatabase db) {  
//查询获得游标  
Cursor cursor = db.query ("usertable",null,null,null,null,null,null);  
   
//判断游标是否为空  
if(cursor.moveToFirst() {  
//遍历游标  
for(int i=0;i<cursor.getCount();i  ){  
cursor.move(i);  
//获得ID  
int id = cursor.getInt(0);  
//获得用户名  
String username=cursor.getString(1);  
//获得密码  
String password=cursor.getString(2);  
//输出用户信息 System.out.println(id ":" sname ":" snumber);  
}  
}  
}

private void drop(SQLiteDatabase db){  
//删除表的SQL语句  
String sql ="DROP TABLE stu_table";  
//执行SQL  
db.execSQL(sql);  
} 

package com.lingdududu.testSQLite;
 
import com.lingdududu.testSQLiteDb.StuDBHelper;
 
import android.app.Activity;
import android.content.ContentValues;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
/*
* @author lingdududu
*/
public class SQLiteActivity extends Activity {
/** Called when the activity is first created. */
//声明各个按钮
private Button createBtn;
private Button insertBtn;
private Button updateBtn;
private Button queryBtn;
private Button deleteBtn;
private Button ModifyBtn;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
 
//调用creatView方法
creatView();
//setListener方法
setListener();
}
 
//通过findViewById获得Button对象的方法
private void creatView(){
createBtn = (Button)findViewById(R.id.createDatabase);
updateBtn = (Button)findViewById(R.id.updateDatabase);
insertBtn = (Button)findViewById(R.id.insert);
ModifyBtn = (Button)findViewById(R.id.update);
queryBtn = (Button)findViewById(R.id.query);
deleteBtn = (Button)findViewById(R.id.delete);
}
 
//为按钮注册监听的方法
private void setListener(){
createBtn.setOnClickListener(new CreateListener());
updateBtn.setOnClickListener(new UpdateListener());
insertBtn.setOnClickListener(new InsertListener());
ModifyBtn.setOnClickListener(new ModifyListener());
queryBtn.setOnClickListener(new QueryListener());
deleteBtn.setOnClickListener(new DeleteListener());
}
 
//创建数据库的方法
class CreateListener implements OnClickListener{
 
@Override
public void onClick(View v) {
//创建StuDBHelper对象
StuDBHelper dbHelper = new StuDBHelper(SQLiteActivity.this,"stu_db",null,1);
//得到一个可读的SQLiteDatabase对象
SQLiteDatabase db =dbHelper.getReadableDatabase();
}
}
 
//更新数据库的方法
class UpdateListener implements OnClickListener{
 
@Override
public void onClick(View v) {
// 数据库版本的更新,由原来的1变为2
StuDBHelper dbHelper = new StuDBHelper(SQLiteActivity.this,"stu_db",null,2);
SQLiteDatabase db =dbHelper.getReadableDatabase();
}
}
 
//插入数据的方法
class InsertListener implements OnClickListener{
 
@Override
public void onClick(View v) {
 
StuDBHelper dbHelper = new StuDBHelper(SQLiteActivity.this,"stu_db",null,1);
//得到一个可写的数据库
SQLiteDatabase db =dbHelper.getWritableDatabase();
 
//生成ContentValues对象 //key:列名，value:想插入的值
ContentValues cv = new ContentValues();
//往ContentValues对象存放数据，键-值对模式
cv.put("id", 1);
cv.put("sname", "xiaoming");
cv.put("sage", 21);
cv.put("ssex", "male");
//调用insert方法，将数据插入数据库
db.insert("stu_table", null, cv);
//关闭数据库
db.close();
}
}
 
//查询数据的方法
class QueryListener implements OnClickListener{
 
@Override
public void onClick(View v) {
 
StuDBHelper dbHelper = new StuDBHelper(SQLiteActivity.this,"stu_db",null,1);
//得到一个可写的数据库
SQLiteDatabase db =dbHelper.getReadableDatabase();
//参数1：表名
//参数2：要想显示的列
//参数3：where子句
//参数4：where子句对应的条件值
//参数5：分组方式
//参数6：having条件
//参数7：排序方式
Cursor cursor = db.query("stu_table", new String[]{"id","sname","sage","ssex"}, "id=?", new String[]{"1"}, null, null, null);
while(cursor.moveToNext()){
String name = cursor.getString(cursor.getColumnIndex("sname"));
String age = cursor.getString(cursor.getColumnIndex("sage"));
String sex = cursor.getString(cursor.getColumnIndex("ssex"));
System.out.println("query------->"   "姓名：" name " " "年龄：" age " " "性别：" sex);
}
//关闭数据库
db.close();
}
}
 
//修改数据的方法
class ModifyListener implements OnClickListener{
 
@Override
public void onClick(View v) {
 
StuDBHelper dbHelper = new StuDBHelper(SQLiteActivity.this,"stu_db",null,1);
//得到一个可写的数据库
SQLiteDatabase db =dbHelper.getWritableDatabase();
ContentValues cv = new ContentValues();
cv.put("sage", "23");
//where 子句 "?"是占位符号，对应后面的"1",
String whereClause="id=?";
String [] whereArgs = {String.valueOf(1)};
//参数1 是要更新的表名
//参数2 是一个ContentValeus对象
//参数3 是where子句
db.update("stu_table", cv, whereClause, whereArgs);
}
}
 
//删除数据的方法
class DeleteListener implements OnClickListener{
 
@Override
public void onClick(View v) {
 
StuDBHelper dbHelper = new StuDBHelper(SQLiteActivity.this,"stu_db",null,1);
//得到一个可写的数据库
SQLiteDatabase db =dbHelper.getReadableDatabase();
String whereClauses = "id=?";
String [] whereArgs = {String.valueOf(2)};
//调用delete方法，删除数据
db.delete("stu_table", whereClauses, whereArgs);
}
}
}

package com.lingdududu.testSQLiteDb; 
   
import android.content.Context; 
import android.database.sqlite.SQLiteDatabase; 
import android.database.sqlite.SQLiteDatabase.CursorFactory; 
import android.database.sqlite.SQLiteOpenHelper; 
import android.util.Log; 
   
public class StuDBHelper extends SQLiteOpenHelper { 
   
private static final String TAG = "TestSQLite"; 
public static final int VERSION = 1; 
   
//必须要有构造函数 
public StuDBHelper(Context context, String name, CursorFactory factory, 
int version) { 
super(context, name, factory, version); 
} 
   
// 当第一次创建数据库的时候，调用该方法  
public void onCreate(SQLiteDatabase db) { 
String sql = "create table stu_table(id int,sname varchar(20),sage int,ssex varchar(10))"; 
//输出创建数据库的日志信息 
Log.i(TAG, "create Database------------->"); 
//execSQL函数用于执行SQL语句 
db.execSQL(sql); 
} 
   
//当更新数据库的时候执行该方法 
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { 
//输出更新数据库的日志信息 
Log.i(TAG, "update Database------------->"); 
} 
}

<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
android:orientation="vertical" 
android:layout_width="fill_parent" 
android:layout_height="fill_parent" 
> 
<TextView  
android:layout_width="fill_parent"  
android:layout_height="wrap_content"  
android:text="@string/hello" 
/> 
<Button 
android:id="@ id/createDatabase" 
android:layout_width="fill_parent"  
android:layout_height="wrap_content"  
android:text="创建数据库" 
/>  
<Button 
android:id="@ id/updateDatabase" 
android:layout_width="fill_parent"  
android:layout_height="wrap_content"  
android:text="更新数据库" 
/>  
<Button 
android:id="@ id/insert" 
android:layout_width="fill_parent"  
android:layout_height="wrap_content"  
android:text="插入数据" 
/> 
<Button 
android:id="@ id/update" 
android:layout_width="fill_parent"  
android:layout_height="wrap_content"  
android:text="更新数据" 
/> 
<Button 
android:id="@ id/query" 
android:layout_width="fill_parent"  
android:layout_height="wrap_content"  
android:text="查询数据" 
/> 
<Button 
android:id="@ id/delete" 
android:layout_width="fill_parent"  
android:layout_height="wrap_content"  
android:text="删除数据" 
/> 
</LinearLayout>