android sqlite 判断表和表中字段是否存在方法

/**

    *检查某表是否存在    * @param tableName 表名    * @return  true:存在  false：不存在    */public boolean tabIsExist(String tabName){        boolean result = false;        if(tabName == null){                return false;        }        Cursor cursor = null;        try {                               String sql = "select count(*) as c from sqlite_master where type ='table' and name ='"+tabName.trim()+"' ";                cursor = mUDB.rawQuery(sql, null);                if(cursor.moveToNext()){                        int count = cursor.getInt(0);                        if(count>0){                                result = true;                        }                }                        } catch (Exception e) {        }                        return result;}/**    *检查表中某列是否存在    * @param db    * @param tableName 表名    * @param columnName 列名    * @return  true:存在  false：不存在    */    private boolean checkColumnExists2(SQLiteDatabase db, String tableName , String columnName) {        boolean result = false ;        Cursor cursor = null ;        try{            cursor = db.rawQuery( "select * from sqlite_master where name = ? and sql like ?"               , new String[]{tableName , "%" + columnName + "%"} );            result = null != cursor && cursor.moveToFirst() ;        }catch (Exception e){            Log.e("","checkColumnExists2..." + e.getMessage()) ;        }finally{            if(null != cursor && !cursor.isClosed()){                cursor.close() ;            }        }        return result ;    }