androd SQLite 自己写的数据库操作类
发布时间：2020-12-12 20:39:57 所属栏目：百科 来源：网络整理
导读：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
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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,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[] 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,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(); } }（编辑：李大同） 【声明】本站内容均来自网络，其相关言论仅代表作者个人观点，不代表本站立场。若无意侵犯到您的权利，请及时与联系站长删除相关内容! |