import android.app.Activity;import android.content.ContentValues;import android.database.Cursor;import android.database.sqlite.SQLiteDatabase;import android.os.Bundle;import android.util.Log;import android.view.Menu;import android.view.MenuItem;public class MainActivity extends Activity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); SQLiteDatabase db = openOrCreateDatabase("stu.db", MODE_PRIVATE, null); // 即只能存储int类型,写成integer比int更好;autoincrement即组件自增 db.execSQL("create table if not exits stutb(_id integer private key autoincrement,name text not null,sex text not null, age text not null)"); /* * table指表的名字 * nullColumnHack为默认值,null * values是contentvalue,类似于HashMap */ ContentValues values=new ContentValues(); values.put("name","张三"); values.put("sex", "男"); values.put("age", 19); //db.insert("stutb", null, values)返回long值,可以赋值,有用再用,没用也没事 long rowId= db.insert("stutb", null, values); values.clear(); values.put("name","张三丰"); values.put("sex", "男"); values.put("age", 99); db.insert("stutb", null, values); values.clear(); values.put("name","张三疯"); values.put("sex", "男"); values.put("age", 59); db.insert("stutb", null, values); values.clear(); values.put("name","张四"); values.put("sex", "男"); values.put("age", 29); db.insert("stutb", null, values); values.clear(); values.put("name","张五"); values.put("sex", "男"); values.put("age", 59); db.insert("stutb", null, values); values.clear(); values.put("sex", "女"); //查询条件 db.update("stutb", values, "_id>?", new String[]{"3"});//将id大于三的性别全部改成女 db.delete("stutb", "name like?", new String[]{"%丰%"});//删除所有名字中带有丰的人 Cursor c= db.query("studb", null, "_id>?", new String[]{"0"}, null, null, "name");//查询 if (c!=null) { String[] columns= c.getColumnNames(); while (c.moveToNext()) { for (String columnName:columns) { Log.d("Main", c.getString(c.getColumnIndex(columnName))); } }c.close();//while之外,进行游标的关闭 }db.close();//if之外,进行db的关闭 }}
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