一：创建数据库
package com.itcode.mysqlite;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteDatabase.CursorFactory;
import android.database.sqlite.SQLiteOpenHelper;
/**
* 继承SQLiteOpenHelper，创建数据库
* @author Administrator
*
*/
public class MySQLiteOpenHelper extends SQLiteOpenHelper{
//一：声明构造函数
/**
* @param context 当前应用的环境，用来确定数据库目录
* @param name 数据库文件的名字
* @param factory 游标工厂，用来创建结果集对象
* @param version 数据库版本 从1开始
*/
public MySQLiteOpenHelper(Context context) {
super(context, "itcode.db", null, 1);
}
//二：重写onCreate方法 数据库被创建时调用
public void onCreate(SQLiteDatabase db) {
System.out.println("MySQLiteOpenHelper-->onCreate 被调用！");
//1.创建数据库
db.execSQL("create table account(_id INTEGER PRIMARY KEY AUTOINCREMENT,name VARCHAR(20),balance INTEGER)");
// db.execSQL("CREATE TABLE account(_id INTEGER PRIMARY KEY AUTOINCREMENT, name VARCHAR(20))"); // 执行一条SQL语句
}
//三：重写onUpgreade方法，数据库时调用
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// System.out.println("MySQLiteOpenHelper-->onUpgrade 被调用");
// db.execSQL("alter table account ADD balance integer");
// db.execSQL("ALTER TABLE account ADD balance INTEGER");
}
}
二：对数据库进行CRUD操作
package com.itcode.mysqlite;
import java.util.ArrayList;
import java.util.List;
import android.content.Context;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
public class AccountDao {
//一：创建AccountDao时依据当前context创建数据库
private MySQLiteOpenHelper mySQLiteOpenHelper;
public AccountDao(Context context){
mySQLiteOpenHelper = new MySQLiteOpenHelper(context);
}
//二：增:传进来一个Account,将此对象加入数据库
public int add(Account a){
//1.获取相应的(可写的)数据库
SQLiteDatabase writableDatabase = mySQLiteOpenHelper.getWritableDatabase();
//2.执行语句
writableDatabase.execSQL("insert into account(name,balance) values(?,?)", new Object[]{a.getName(),a.getBalance()});
//3.获取插入的数据集：
Cursor rawQuery = writableDatabase.rawQuery("select _id from account order by _id desc limit 1", null);
rawQuery.moveToNext();
int id = rawQuery.getInt(rawQuery.getColumnIndex("_id"));
//4.关闭数据库
return id;
}
//三：删：根据id删除数据库中相应的数据项
public void delete(int id){
//1.获取相应的(可写的)数据库
SQLiteDatabase writableDatabase = mySQLiteOpenHelper.getWritableDatabase();
//2.执行删除语句
writableDatabase.execSQL("Delete from account where _id = ?",new Object[]{id});
//3.关闭数据库
writableDatabase.close();
}
//四：改：传进来一个Account，根据Account的对象的id修改name 和balance
public void update(Account a){
//1.获取相应的（可写的）数据库
SQLiteDatabase writableDatabase = mySQLiteOpenHelper.getWritableDatabase();
//2.执行更新语句
writableDatabase.execSQL("update account set name=?,balance = ? where _id = ?",new Object[]{a.getName(),a.getBalance(),a.getId()});
//3.关闭数据库
writableDatabase.close();
}
//五：查：根据id查询数据库
public Account query(int id){
//1.获取相应的（可读的）数据库
SQLiteDatabase readableDatabase = mySQLiteOpenHelper.getReadableDatabase();
//2.执行更新语句
Cursor rawQuery = readableDatabase.rawQuery("select * from account where _id=?", new String[]{String.valueOf(id)});
//3.将查询到的数据赋值给Account对象
Account a = null;
while(rawQuery.moveToNext()){
Integer balance = Integer.valueOf(rawQuery.getString(rawQuery.getColumnIndex("balance")));
String name = rawQuery.getString(rawQuery.getColumnIndex("name"));
a = new Account(id,name,balance);
}
//3.关闭结果集与数据库
rawQuery.close();
readableDatabase.close();
return a;
}
//六：查询所有，将查询到的所有数据放在list集合中返回
public List<Account> queryAll(){
List<Account> list = new ArrayList<Account>();
Account a = null;
//1.获取相应的（可读的）数据库
SQLiteDatabase readableDatabase = mySQLiteOpenHelper.getReadableDatabase();
Cursor rawQuery = readableDatabase.rawQuery("Select * from account",null);
while(rawQuery.moveToNext()){
Integer id = Integer.valueOf(rawQuery.getString(rawQuery.getColumnIndex("_id")));
String name = rawQuery.getString(rawQuery.getColumnIndex("name"));
Integer balance = Integer.valueOf(rawQuery.getString(rawQuery.getColumnIndex("balance")));
a = new Account(id,name,balance);
list.add(a);
}
//3.关闭资源
rawQuery.close();
readableDatabase.close();
return list;
}
//七：分页查询：传入要查询第几页，每页显示几条数据，将查询到的数据放在list集合中返回
public List<Account> queryPage(int pageNum,int pageSize){
List<Account> list = new ArrayList<Account>();
Account a = null;
String index = String.valueOf((pageNum-1)*pageSize);
String count = String.valueOf(pageSize);
//1.获取相应的（可读的）数据库
SQLiteDatabase readableDatabase = mySQLiteOpenHelper.getReadableDatabase();
//2.执行相应的查询语句
Cursor rawQuery = readableDatabase.rawQuery("select * from account limit ?,?", new String[]{index,count});
while(rawQuery.moveToNext()){
Integer id = Integer.valueOf(rawQuery.getString(rawQuery.getColumnIndex("_id")));
String name = rawQuery.getString(rawQuery.getColumnIndex("name"));
Integer balance = Integer.valueOf(rawQuery.getString(rawQuery.getColumnIndex("balance")));
a = new Account(id,name,balance);
list.add(a);
}
//3.关闭相应的资源
rawQuery.close();
readableDatabase.close();
return list;
}
//八：查询总记录条数
public int queryCount(){
//1.获取相应的（可读的）数据库
SQLiteDatabase readableDatabase = mySQLiteOpenHelper.getReadableDatabase();
//2.执行相应的语句
Cursor rawQuery = readableDatabase.rawQuery("select count(*) from account", null);
rawQuery.moveToNext();//不加此句可否？不能去掉！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！
int count = rawQuery.getInt(0);
//3.关闭资源
rawQuery.close();
readableDatabase.close();
return count;
}
//九：事物管理 从一个Account对象向另一个Account对象汇款，传入参数，fromid,toId,moneySize
public void remit(int fromId,int toId,int moneySize){
SQLiteDatabase writableDatabase = null;
try {
//1.获取相应的（可写的）数据库
writableDatabase = mySQLiteOpenHelper.getWritableDatabase();
//2.开启事物
writableDatabase.beginTransaction();
//3.执行相应的语句
writableDatabase.execSQL("update account set balance=balance-? where _id = ?", new Object[]{moneySize,fromId});
writableDatabase.execSQL("update account set balance=balance+? where _id = ?",new Object[]{moneySize,toId});
//4.设置成功标记
writableDatabase.setTransactionSuccessful();
//5.关闭资源
writableDatabase.close();
} catch (Exception e) {
//6.结束事务，会把最后一次成功标记之前的事务提交
writableDatabase.endTransaction();
e.printStackTrace();
}
}
}
三：对CRUD的方法的测试：
package com.itcode.mysqlite;
import java.util.List;
import java.util.Random;
import android.database.sqlite.SQLiteDatabase;
import android.test.AndroidTestCase;
public class SQLiteTest extends AndroidTestCase{
//1.测试创建数据库的方法
public void testCreateDB(){
//1.创建数据库
MySQLiteOpenHelper helper = new MySQLiteOpenHelper(getContext());
//2.得到相应的数据库
SQLiteDatabase db = helper.getWritableDatabase();
db.execSQL("INSERT INTO account(_id,name, balance) VALUES(1,'fuck', 10000)");
}
//2.测试添加数据的方法
public void testAdd(){
AccountDao dao = new AccountDao(getContext());// Context android.test.AndroidTestCase.getContext()
for(int i=1;i<100;i++){
dao.add(new Account("Test" + i,new Random().nextInt(10000)));
}
}
//3.测试删除数据的方法
public void testDelete(){
AccountDao dao = new AccountDao(getContext());
for(int i=100;i<200;i++){
dao.delete(i);
}
}
//4.测试修改数据的方法
public void testUpdate(){
AccountDao dao = new AccountDao(getContext());
Account a = new Account(1,"fuck you!!!~",999);
dao.update(a);
}
//5.测试查询数据的方法，根据id查询数据库
public void testQuery(){
AccountDao dao = new AccountDao(getContext());
System.out.println(dao.query(1));
System.out.println(dao.query(3));
System.out.println(dao.query(4));
}
//6.测试查询所有的方法
public void testQueryAll(){
AccountDao dao = new AccountDao(getContext());
List<Account> list =null;
list = dao.queryAll();
for (Account account : list) {
System.out.println(account);
}
}
//7.测试分布查询的方法
public void testQueryPage(){
AccountDao dao = new AccountDao(getContext());
List<Account> list = null;
list = dao.queryPage(2, 10);
for (Account account : list) {
System.out.println(account);
}
}
//8.测试查询总记录条数的方法
public void testQueryCount(){
AccountDao dao = new AccountDao(getContext());
int count = dao.queryCount();
System.out.println(count);
}
}
