android操作SQLite增删改减实现代码

//创建表
public boolean createTable(){
SQLiteDatabase db=dbHelper.getWritableDatabase();
String sql="CREATE TABLE IF NOT EXISTS "+TABLE_NAME+"(ID INTEGER PRIMARY KEY,Name VARCHAR,Age INTEGER)";
try{
db.execSQL(sql);
return true;
}catch(SQLException ex){
Log.d(tag, "create table failure");
return false;
}
}
//添加数据
public boolean addData(){
String name=etname.getText().toString();
String age=etage.getText().toString();
SQLiteDatabase db=dbHelper.getWritableDatabase();
String sql="insert into "+TABLE_NAME+"(name,age) values ('"+name+"','"+age+"')";
try{
db.execSQL(sql);
return true;
}catch(SQLException ex){
Log.d(tag, "add data failure");
return false;
}
}
//修改
public boolean updateData(){
SQLiteDatabase db=dbHelper.getWritableDatabase();
String sql="update "+TABLE_NAME+" set age='2' where name like 'cb'";
Object[] bindArgs={"cb"};
try{
db.execSQL(sql, bindArgs);
return true;
}catch(SQLException ex){
Log.d(tag, "update data failure");
return false;
}
}

//查询 public void selectData(){
SQLiteDatabase db=dbHelper.getReadableDatabase();
String[] columns={"name"};
Cursor cursor=db.query(TABLE_NAME, columns, null, null, null, null, null);
String names="";
while(cursor.moveToNext()){
int c=cursor.getColumnIndexOrThrow("Name");
String name=cursor.getString(c);
//<= >
//String name=cursor.getString(0);//只查询了一列
if(names==""){
names=name;
}else{
names=names+"\n"+name;
}
}
tvname.setText(names);
//另外一种查询方法
//String sql="select name from "+TABLE_NAME;
//Curosr cursor=db.rawQuery(sql, null);
}