Android -- 数据库1

来源：互联网发布：华为it应用技术工程师编辑：程序博客网时间：2024/06/07 04:30
数据库的基本操作。
package com.serviatech.testdb;import android.annotation.SuppressLint;import android.app.Activity;import android.database.Cursor;import android.database.sqlite.SQLiteDatabase;import android.os.Bundle;@SuppressLint("SdCardPath")public class MainActivity extends Activity {final static String PATH_DB = "/sdcard/test.db";@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);// 创建数据库SQLiteDatabase db = SQLiteDatabase.openOrCreateDatabase(PATH_DB, null);// 删除/创建表db.execSQL("drop table user_info");db.execSQL("create table user_info(user_id integer primary key,user_name varchar(255),user_pass varchar(255))");// 插入数据db.execSQL("insert into user_info values(1,'aizizai1','shane1234')");db.execSQL("insert into user_info values(2,'aizizai2','shane1234')");db.execSQL("insert into user_info values(3,'aizizai3','shane1234')");db.execSQL("insert into user_info values(4,'aizizai4','shane1234')");// 修改db.execSQL("update user_info set user_pass='shane1111' where user_id = 1");db.execSQL("update user_info set user_pass='shane2222' where user_id = 2;");db.execSQL("update user_info set user_pass='shane3333' where user_id = 3;");db.execSQL("update user_info set user_pass='shane4444' where user_id = 4;");// 删除数据db.execSQL("delete from user_info  where user_id = 1");// 查询Cursor cursor = db.rawQuery("select * from user_info", null);System.out.println("@@@ getColumnCount: " + cursor.getColumnCount());System.out.println("@@@ getColumnName(0): " + cursor.getColumnName(0));System.out.println("@@@ getColumnName(1): " + cursor.getColumnName(1));System.out.println("@@@ getColumnName(2): " + cursor.getColumnName(2));cursor.moveToFirst();System.out.println("@@@ getString(0): " + cursor.getString(0));System.out.println("@@@ getString(1): " + cursor.getString(1));System.out.println("@@@ getString(2): " + cursor.getString(2));printCursor(cursor);cursor.close();// 关闭if (db != null && db.isOpen())db.close();}/** * 打印数据库内容 *  * @param cursor * @data 2015-7-24 下午1:30:53 */public void printCursor(Cursor cursor) {System.out.println("=============================");// 获取列总数int columnSum = cursor.getColumnCount();// 获取列名字String[] columnNames = cursor.getColumnNames();StringBuilder sb = new StringBuilder();for (int i = 0; i < columnNames.length; i++) {sb.append(" " + columnNames[i]);}System.out.println(sb.toString());sb.setLength(0);cursor.moveToFirst();do {for (int i = 0; i < columnSum; i++) {sb.append(" " + cursor.getString(i));}sb.append("\n");} while (cursor.moveToNext());System.out.println(sb.toString());System.out.println("=============================");}}
源码
http://download.csdn.net/detail/u012587637/8929645
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