SQliteDatabase详解

Cursor cursor = db.rawQuery(“select * from person”, null); 
while (cursor.moveToNext()) { 
int personid = cursor.getInt(0); //获取第一列的值,第一列的索引从0开始 
String name = cursor.getString(1);//获取第二列的值 
int age = cursor.getInt(2);//获取第三列的值 
} 
cursor.close(); 

SQLiteDatabase db = databaseHelper.getWritableDatabase(); 
ContentValues values = new ContentValues(); 
values.put("name", "测试数据"); 
values.put("age", 4); 
long rowid = db.insert(“person”, null, values);//返回新添记录的行号，与主键id无关 

SQLiteDatabase db = databaseHelper.getWritableDatabase(); 
db.delete("person", "personid<?", new String[]{"2"}); 
db.close(); 

SQLiteDatabase db = databaseHelper.getWritableDatabase(); 
ContentValues values = new ContentValues(); 
values.put(“name”, “测试数据”);//key为字段名，value为值 
db.update("person", values, "personid=?", new String[]{"1"});  
db.close(); 

SQLiteDatabase db = databaseHelper.getWritableDatabase(); 
Cursor cursor = db.query("person", new String[]{"personid,name,age"}, "name like ?", new String[]{"%传智%"}, null, null, "personid desc", "1,2"); 
while (cursor.moveToNext()) { 
 int personid = cursor.getInt(0); //获取第一列的值,第一列的索引从0开始 
String name = cursor.getString(1);//获取第二列的值 
int age = cursor.getInt(2);//获取第三列的值 
} 
cursor.close(); 
db.close();  

package com.zyq.db;  
import android.app.Activity;  
import android.os.Bundle;  
public class MainActivity extends Activity   
{  
@Override  
public void onCreate(Bundle savedInstanceState)   
{  
super.onCreate(savedInstanceState);  
setContentView(R.layout.main);  
}  
} 

package com.zyq.db;  
import java.util.List;  
import android.test.AndroidTestCase;  
import android.util.Log;  
import com.zyq.service.DBOpenHelper;  
import com.zyq.service.PersonService;  
import com.zyq.voo.Person;  

/** 
 * 测试方法 通过Junit 单元测试 
 * 1.>实例化测试类 
 * 2.>把与应用有关的上下文信息传入到测试类实例 
 * 3.>运行测试方法  
 * @author Administrator 
 * 
 */  
public class PersonServiceTest extends AndroidTestCase  
{  
private final static String TAG="PersonServiceTest";  

/** 
 * 测试创建数据库 
 * @throws Throwable 
 */  
public void testCreateDB() throws Throwable  
{  
DBOpenHelper dbOpenHelper=new DBOpenHelper(this.getContext());  
dbOpenHelper.getReadableDatabase(); //Create and/or open a database.  
}  
/** 
 * 测试新增一条记录 
 * @throws Throwable 
 */  
public void testSave() throws Throwable  
{  
PersonService personService=new PersonService(this.getContext());  
personService.save(new Person("zhangsan","1360215320"));  
personService.save(new Person("lisi","1123"));  
personService.save(new Person("lili","232"));  
personService.save(new Person("wangda","123123"));  
personService.save(new Person("laozhu","234532"));  
}  
/** 
 * 查找一条记录 
 * @throws Throwable 
 */  
public void testFind() throws Throwable  
{  
PersonService personService=new PersonService(this.getContext());  
Person person=personService.find(1);  
Log.i(TAG,person.toString());  
}  
/** 
 * 测试更新一条记录 
 * @throws Throwable 
 */  
public void testUpdate() throws Throwable  
{  
PersonService personService=new PersonService(this.getContext());  
Person person=personService.find(1);  
person.setName("lisi");  
personService.update(person);  
}  
/** 
 * 测试得到所有记录数 
 * @throws Throwable 
 */  
public void testGetCount() throws Throwable  
{  
PersonService personService=new PersonService(this.getContext());  
Log.i(TAG, personService.getCount()+"********");  
}  
/** 
 * 测试分页 
 * @throws Throwable 
 */  
public void testScroll() throws Throwable  
{  
PersonService personService=new PersonService(this.getContext());  
List<Person> persons=personService.getScrollData(3, 3);  
for(Person person:persons)  
{  
Log.i(TAG, person.toString());  
}  
}  
/** 
 * 测试删除一条记录 
 * @throws Throwable 
 */  
public void testDelete() throws Throwable  
{  
PersonService personService=new PersonService(this.getContext());  
personService.delete(5);  
}  
} 


复制代码 代码如下:

package com.zyq.service;  
import android.content.Context;  
import android.database.sqlite.SQLiteDatabase;  
import android.database.sqlite.SQLiteOpenHelper;  
public class DBOpenHelper extends SQLiteOpenHelper  
{  
/** 
 * 如果想额外的增加一个字段（需求） 
 * 可以把版本号更改掉 但必须 >=1 
 * 更改版本号之后 会根据版本号判断是不是上次创建的时候 （目前的版本号和传入的版本号是否一致 ） 
 * 如果不是会执行 onUpgrade（） 方法 
 * @param context 
 */  
public DBOpenHelper(Context context)  
{  
super(context, "zyq.db", null, 2);  
}  
/** 
 * 在数据库创建的时候第一个调用的方法 
 * 适合创建表结构 
 */  
@Override  
public void onCreate(SQLiteDatabase db)  
{  
db.execSQL("CREATE TABLE person (personid integer primary key autoincrement, name varchar(20))");//创建表  
}  
/** 
 * 更新表结构 在数据库版本号发生改变的时候调用 
 * 应用升级  
 */  
@Override  
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion)  
{  
db.execSQL("ALTER TABLE person ADD phone VARCHAR(12) NULL "); //往表中增加一列  
}  
} 


复制代码 代码如下:

<?xml version="1.0" encoding="utf-8"?>  
<manifest xmlns:android="http://schemas.android.com/apk/res/android"  
  package="com.zyq.db"  
  android:versionCode="1"  
  android:versionName="1.0">  
<application android:icon="@drawable/icon" android:label="@string/app_name">  
<uses-library android:name="android.test.runner" />  
<activity android:name=".MainActivity"  
  android:label="@string/app_name">  
<intent-filter>  
<action android:name="android.intent.action.MAIN" />  
<category android:name="android.intent.category.LAUNCHER" />  
</intent-filter>  
</activity>  
</application>  
<uses-sdk android:minSdkVersion="8" />  
<instrumentation android:name="android.test.InstrumentationTestRunner"  
android:targetPackage="com.zyq.db" android:label="Tests for My App" />  
</manifest>  


复制代码 代码如下:

package com.zyq.service;  
import java.util.ArrayList;  
import java.util.List;  
import android.content.Context;  
import android.database.Cursor;  
import android.database.sqlite.SQLiteDatabase;  
import com.zyq.voo.Person;  
public class PersonService  
{  
private DBOpenHelper helper;  
public PersonService(Context context)  
{  
helper=new DBOpenHelper(context);  
}  
/** 
 * 新增一条记录 
 * @param person 
 */  
public void save(Person person)  
{  
SQLiteDatabase db=helper.getWritableDatabase();//Create and/or open a database that will be used for reading and writing  
db.execSQL("INSERT INTO person(name,phone) values(?,?)",new Object[]{person.getName().trim(),person.getPhone().trim()});//使用占位符进行转译  
//  db.close();  不关数据库连接 。可以提高性能 因为创建数据库的时候的操作模式是私有的。  
//代表此数据库，只能被本应用所访问 单用户的，可以维持长久的链接  
}   
/** 
 * 更新某一条记录 
 * @param person 
 */  
public void update(Person person)  
{  
SQLiteDatabase db=helper.getWritableDatabase();  
db.execSQL("update person set phone=?,name=? where personid=?",  
new Object[]{person.getPhone().trim(),person.getName().trim(),person.getId()});  
}  
/** 
 * 根据ID查询某条记录 
 * @param id 
 * @return 
 */  
public Person find(Integer id)  
{  
SQLiteDatabase db=helper.getReadableDatabase();  
Cursor cursor=db.rawQuery("select * from person where personid=?", new String[]{id.toString()});//Cursor 游标和 ResultSet 很像  
if(cursor.moveToFirst())//Move the cursor to the first row. This method will return false if the cursor is empty.  
{  
int personid=cursor.getInt(cursor.getColumnIndex("personid"));  
String name=cursor.getString(cursor.getColumnIndex("name"));  
String phone=cursor.getString(cursor.getColumnIndex("phone"));  

return new Person(personid,name,phone);  
}  
return null;  
}  
/** 
 * 删除某一条记录 
 * @param id 
 */  
public void delete(Integer id)  
{  
SQLiteDatabase db=helper.getWritableDatabase();  
db.execSQL("delete from person where personid=?",  
new Object[]{id});  
}  

/** 
 * 得到记录数 
 * @return 
 */  
public long getCount()  
{  
SQLiteDatabase db=helper.getReadableDatabase();  
Cursor cursor=db.rawQuery("select count(*) from person", null);  
cursor.moveToFirst();  
return cursor.getLong(0);  
}  
/** 
 * 分页查询方法 SQL语句跟MySQL的语法一样 
 * @return 
 */  
public List<Person> getScrollData(int offset,int maxResult)  
{  
List<Person> persons=new ArrayList<Person>();  
SQLiteDatabase db=helper.getReadableDatabase();  
Cursor cursor=db.rawQuery("select * from person limit ?,?",   
new String[]{String.valueOf(offset),String.valueOf(maxResult)});  
while (cursor.moveToNext())  
{  
int personid=cursor.getInt(cursor.getColumnIndex("personid"));  
String name=cursor.getString(cursor.getColumnIndex("name"));  
String phone=cursor.getString(cursor.getColumnIndex("phone"));  

persons.add(new Person(personid,name,phone));  
}  

return persons;  
}  
} 


复制代码 代码如下:

package com.zyq.voo;  
public class Person  
{  
private Integer id;  
private String name;  
private String phone;  

public Person(int personid, String name, String phone)  
{  
this.id=personid;  
this.name=name;  
this.phone=phone;  
}  

public Person(String name, String phone)  
{  
this.name = name;  
this.phone = phone;  
}  
public String toString()  
{  
return "Person [id=" + id + ", name=" + name + ", phone=" + phone + "]";  
}  
public Integer getId()  
{  
return id;  
}  
public void setId(Integer id)  
{  
this.id = id;  
}  
public String getName()  
{  
return name;  
}  
public void setName(String name)  
{  
this.name = name;  
}  
public String getPhone()  
{  
return phone;  
}  
public void setPhone(String phone)  
{  
this.phone = phone;  
}  

  

}