sql简单的语句

Posted 2020-09-22 jzssuanfa

选择：select * from table1 where 范围
插入：insert into table1(field1,field2) values(value1,value2)
删除：delete from table1 where 范围
更新：update table1 set field1=value1 where 范围

查找：select * from table1 where field1 like ’%value1%’ ---like的语法非常精妙，查资料!

			String n=name.getText().toString();
			String e=email.getText().toString();
			//String add="insert into lgx_table(name,email) values(‘lgx‘,‘xxx‘)";
			String add="insert into lgx_table(name,email) values(?,?
)";
			db.execSQL(add,new String[]{n,e});

android简单的数据库创建和使用

package com.example.dbdemo;

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteDatabase.CursorFactory;
import android.database.sqlite.SQLiteOpenHelper;

public class DataBd extends SQLiteOpenHelper {

	public DataBd(Context context, String name, CursorFactory factory,
			int version) {
		super(context, name, factory, version);
	}

	@Override
	public void onCreate(SQLiteDatabase db) {
		db.execSQL("create table lgx_table(_id integer primary key autoincrement,name varchar(20), email varchar(50))");
	}

	@Override
	public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

	}

}

package com.example.dbdemo;

import android.app.Activity;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class MainActivity extends Activity {
	DataBd dataBd;
	SQLiteDatabase db;
	EditText name,email;
	TextView text;

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);

		dataBd = new DataBd(this, "lgx", null, 2);
		db = dataBd.getReadableDatabase();
		name=(EditText) findViewById(R.id.name);
		email=(EditText) findViewById(R.id.email);
		text=(TextView) findViewById(R.id.text);
	}

	public void dbClick(View v) {
		switch (v.getId()) {
		case R.id.add:
			String n=name.getText().toString();
			String e=email.getText().toString();
			//String add="insert into lgx_table(name,email) values(‘lgx‘,‘xxx‘)";
			String add="insert into lgx_table(name,email) values(?,?)";
			db.execSQL(add,new String[]{n,e});
			break;
		case R.id.delete:
			
			break;
		case R.id.update:

			break;
		case R.id.select:
			String select="select * from lgx_table ";
			//db.execSQL(select);
			Cursor cursor=db.rawQuery(select, null);
			while (cursor.moveToNext()) {
				String name=cursor.getString(cursor.getColumnIndex("name"));
				String email=cursor.getString(cursor.getColumnIndex("email"));
				text.setText(name+"    "+email);
			}
			break;

		default:
			break;
		}
	}

}