androd SQLite 自己写的数据库操作类

package com.db;

import android.content.ContentValues;

import android.content.Context;

import android.database.Cursor;

import android.database.sqlite.SQLiteDatabase;

import android.database.sqlite.SQLiteDatabase.CursorFactory;

import android.database.sqlite.SQLiteOpenHelper;

import android.util.Log;

public class MyHelper extends SQLiteOpenHelper{

};

public MyHelper(Context context, String name,

CursorFactory factory, int version) {

super(context, name, factory, version);

}

@Override

public void onCreate(SQLiteDatabase db) {

//这儿添加建表语句

db.execSQL("你的SQL语句");

}

@Override

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

}

/**

* 执行一条SQL语句

* @param sql

*/

public void executeSQL(String sql)

{

SQLiteDatabase db = null;

try{

db = this.getWritableDatabase();

db.execSQL(sql);

}catch(Exception e){

e.printStackTrace();

}finally{

db.close();

}

}

/**

* 执行一条SQL语句，返回一个游标

* @param sql

* @return

*/

public Cursor executeSQLwithCursorReturn(String sql)

{

Cursor retCursor = null;

SQLiteDatabase db = null;

try{

db = this.getReadableDatabase();

retCursor = db.rawQuery(sql, null);

}catch(Exception e){

Log.d("qiaoning_debug", "DB ERROR");

e.printStackTrace();

}

return retCursor;

}

/**

* 执行一条SQL语句，判断是否存在该记录，存在返回true，不存在返回false

* @param sql

* @return

*/

public boolean isExist(String sql)

{

boolean retBoolean = false;

Cursor c = null;

SQLiteDatabase db = null;

try{

db = this.getReadableDatabase();

c = db.rawQuery(sql, null);

if(c.getCount() == 0)

{

retBoolean = false;

}

else

{

retBoolean = true;

}

}catch(Exception e){

Log.e("ERROR", e.toString());

//e.printStackTrace();

}finally{

db.close();

}

return retBoolean;

}

/**

*

* @param table

* @param columns

* @param selection

* @param selectionArgs

* @param groupBy

* @param having

* @param orderBy

* @return

*/

public Cursor select(String table,String[] columns,String selection,

String[] selectionArgs,String groupBy,String having,String orderBy)

{

SQLiteDatabase db = null;

Cursor cursor = null;

try {

db = this.getReadableDatabase();

cursor = db.query(table, columns, selection, selectionArgs, groupBy, having, orderBy);

} catch (Exception e) {

// TODO: handle exception

}finally{

db.close();

}

return cursor;

}

/**

*

* @param table

* @param fields

* @param values

* @return the row ID of the newly inserted row, or -1 if an error occurred

*/

public long insert(String table, String[] fields, String[] values)

{

SQLiteDatabase db = this.getWritableDatabase();

ContentValues cv = new ContentValues();

for(int i = 0;i < fields.length;i ++)

{

cv.put(fields[i], values[i]);

}

return db.insert(table, null, cv);

}

/**

*

* @param table

* @param cv

* @return the row ID of the newly inserted row, or -1 if an error occurred

*/

public long insertWithContentValues(String table,ContentValues cv)

{

SQLiteDatabase db = this.getWritableDatabase();

long i = 0;

i = db.insert(table, null, cv);

db.close();

return i;

}

/**

*

* @param table

* @param cv

* @param whereClause

* @param whereArgs

* @return the number of rows affected

*/

public int updateTableWithContentValues(String table,ContentValues cv,String whereClause,String[] whereArgs)

{

SQLiteDatabase db = this.getWritableDatabase();

int i = 0;

i = db.update(table, cv, whereClause, whereArgs);

return i;

}

/**

* @param table

* @param updateFields

* @param updateValues

* @param whereClause

* @param whereArgs

* @return

*/

public int update(String table,String[] updateFields,String[] updateValues,

String whereClause , String[] whereArgs)

{

SQLiteDatabase db = this.getWritableDatabase();

ContentValues cv = new ContentValues();

for(int i=0;i<updateFields.length;i++)

{

cv.put(updateFields[i], updateValues[i]);

}

return db.update(table, cv, whereClause, whereArgs);

}

/**

* @param table

* @param where

* @param whereArgs

* @return

*/

public int delete(String table,String where,String[] whereArgs)

{

SQLiteDatabase db = this.getWritableDatabase();

return db.delete(table, where, whereArgs);

}

@Override

public synchronized void close() {

// TODO Auto-generated method stub

super.close();

}

}