当你还不能写出自己满意的程序时，你就不要去睡觉。

public class DBOpenHelper extends sqliteOpenHelper{

public DBOpenHelper(Context context,String name) {

super(context,name,null,1);

// TODO Auto-generated constructor stub

}

public DBOpenHelper(Context context,String name,CursorFactory factory,

int version) {

super(context,factory,version);

// TODO Auto-generated constructor stub

}

@Override//首次创建数据库的时候调用 一般可以把建库 建表的操作

public void onCreate(sqliteDatabase db) {

// TODO Auto-generated method stub

db.execsql("create table if not exists stutb(_id integer primary key autoincrement,name text not null,sex text not null,age integer not null)");

db.execsql("insert into stutb(name,sex,age)values('张三','女',18)");

}

@Override//当数据库的版本发生变化的时候 会自动执行

public void onUpgrade(sqliteDatabase db,int oldVersion,int newVersion) {

// TODO Auto-generated method stub

}

}

查找：

private void queryall(sqliteDatabase db) {
Cursor cusor = db.query("stutb",new String[]{"name","sex","age"},"_id desc");
for (cusor.moveToFirst(); !cusor.isAfterLast(); cusor.moveToNext()) {
String id,age,sex;
id = cusor.getLong(cusor.getColumnIndex("id"))+"";
age = cusor.getLong(cusor.getColumnIndex("age"))+"";
name = cusor.getString(cusor.getColumnIndex("name"));
sex = cusor.getString(cusor.getColumnIndex("sex"));
Log.i("info","id: " + id + "name" + name + "sex" + sex + "age" + age);
}
cusor.close();


}


private void qureyByName(String mName,sqliteDatabase db) {
Cursor cusor = db.query("stutb","name=?",new String[]{mName},null);
String id,sex;
if (cusor.moveToFirst()) {
id = cusor.getLong(cusor.getColumnIndex("id"))+"";
age = cusor.getLong(cusor.getColumnIndex("age"))+"";
name = cusor.getString(cusor.getColumnIndex("name"));
sex = cusor.getString(cusor.getColumnIndex("sex"));
Toast.makeText(this,id + name + sex + age + "",Toast.LENGTH_LONG).show();
Log.i("info","id: " + id + "name" + name + "sex" + sex + "age" + age);
} else {
Toast.makeText(this,"no query result",Toast.LENGTH_LONG).show();
}
}


增加： sqliteDatabase db = openOrCreateDatabase("stu.db",MODE_PRIVATE,null);
db.execsql("create table if not exists stutb(_id integer primary key autoincrement,age integer not null)");
ContentValues values = new ContentValues();
values.put("name","张三");
values.put("sex","男");
values.put("age",19);
long rowId = db.insert("stutb",values);
values.clear();

删除：

db.update("stutb",values,"_id>?",new String[]{"3"});//将全部id>3的人的性别改成女
db.delete("stutb","name like ?",new String[]{"%丰%"});//删除所有名字中带有丰的人
Cursor c = db.query("stutb",new String[]{"0"},"name");
if (c!=null) {
String [] columns= c.getColumnNames();
while (c.moveToNext()) {
for (String columnName : columns) {
Log.i("info",c.getString(c.getColumnIndex(columnName)));
}
}
c.close();
}
db.close();
public class MainActivity extends Activity {


@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//每个程序都有自己的数据库 默认情况下是各自互相不干扰
//创建一个数据库 并且打开
sqliteDatabase db = openOrCreateDatabase("user.db",null);
db.execsql("create table if not exists usertb (_id integer primary key autoincrement,age integer not null,sex text not null )");
db.execsql("insert into usertb(name,sex,age) values('张三',18)");
db.execsql("insert into usertb(name,age) values('李四',19)");
db.execsql("insert into usertb(name,age) values('王五','男',20)");

Cursor c = db.rawQuery("select * from usertb",null);
if (c!=null) {
while (c.moveToNext()) {
Log.i("info","_id:"+c.getInt(c.getColumnIndex("_id")));
Log.i("info","name:"+c.getString(c.getColumnIndex("name")));
Log.i("info","age:"+c.getInt(c.getColumnIndex("age")));
Log.i("info","sex:"+c.getString(c.getColumnIndex("sex")));
Log.i("info","!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!");
}
c.close();
}
db.close();
}

public class MainActivity extends Activity {


@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//每个程序都有自己的数据库 默认情况下是各自互相不干扰
//创建一个数据库 并且打开
sqliteDatabase db = openOrCreateDatabase("user.db",null);
db.execsql("create table if not exists usertb (_id integer primary key autoincrement,sex text not null )");
db.execsql("insert into usertb(name,18)");
db.execsql("insert into usertb(name,19)");
db.execsql("insert into usertb(name,20)");

Cursor c = db.rawQuery("select * from usertb",null);
if (c!=null) {
while (c.moveToNext()) {
Log.i("info","_id:"+c.getInt(c.getColumnIndex("_id")));
Log.i("info","name:"+c.getString(c.getColumnIndex("name")));
Log.i("info","age:"+c.getInt(c.getColumnIndex("age")));
Log.i("info","sex:"+c.getString(c.getColumnIndex("sex")));
Log.i("info","!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!");
}
c.close();
}
db.close();
}

public class MainActivity extends Activity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); sqliteDatabase db = openOrCreateDatabase("stu.db",null); db.execsql("create table if not exists stutb(_id integer primary key autoincrement,age integer not null)"); ContentValues values = new ContentValues(); values.put("name","张三"); values.put("sex","男"); values.put("age",19); long rowId = db.insert("stutb",values); values.clear(); values.put("name","张三丰"); values.put("sex",99); db.insert("stutb","张三疯"); values.put("sex",59); db.insert("stutb","张三峰"); values.put("sex",39); db.insert("stutb","张三封"); values.put("sex",29); db.insert("stutb",values); values.clear(); values.put("sex","女"); db.update("stutb",new String[]{"3"});//将全部id>3的人的性别改成女 db.delete("stutb",new String[]{"%丰%"});//删除所有名字中带有丰的人 Cursor c = db.query("stutb","name"); if (c!=null) { String [] columns= c.getColumnNames(); while (c.moveToNext()) { for (String columnName : columns) { Log.i("info",c.getString(c.getColumnIndex(columnName))); } } c.close(); } db.close(); } }