數據庫的數據添加和查詢

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/*= = = - - - = = =
     sqlite3 數據庫裏添加數據
     = = = - - - = = = */

    //1.定義一個sqlite3的指針
    sqlite3 *db;
    //2.用來接收讀寫數據庫操作是否成功的返回值
    int dbrc;
    //3.轉換數據庫路徑爲UTF8的c風格字符串
    const char* dbFilePathUTF8 = [dbFilePath UTF8String];
    //4.打開數據庫
    dbrc = sqlite3_open(dbFilePathUTF8, &db);
    //判斷是否成功打開
    if (dbrc == SQLITE_OK) {
        NSLog(@"成功打開了數據庫");
    }
    //5.定義執行sql語句的指針
    sqlite3_stmt *dbps;
    //6.定義sql語句
    NSString *insertStatementNS = [NSString stringWithFormat:
                                   @"insert into \"shopping\"\
                                   (item, price, groupid, dateadd)\
                                   values (\"%@\", %@, %d, DATETIME('NOW'))",
                                   @"lll",
                                   @"350",
                                   2];
    //7.將定義的NSString的sql語句，轉換成UTF8的c風格的字符串
    const char *insertStatement = [insertStatementNS UTF8String];


    //8.sql語句的預執行。（判斷sql語句是否符合語法）
    dbrc = sqlite3_prepare_v2
    (db, insertStatement, -1, &dbps, NULL);

    //9.執行sql語句
    dbrc = sqlite3_step (dbps);

    NSLog(@"dbrc = %d",dbrc);




    /*= = = - - - = = =
     數據庫裏讀取數據
     = = = - - - = = =*/

    //1.定義一個查詢語句
    NSString *queryStatementNS =
    @"select key,item,price,groupid,dateadd from shopping";

    //2.將定義的NSString的查詢語句轉換成UTF8的c字符串
    const char *queryStatement = [queryStatementNS UTF8String];

    //3.sql語句的預處理
    dbrc = sqlite3_prepare_v2 (db, queryStatement, -1, &dbps, NULL);
    NSLog (@"prepared statement=%d",dbrc);

    //4.獲取值，要用相匹配的方法去獲取相應類型的值，並要轉換類型
    while ((dbrc = sqlite3_step (dbps)) == SQLITE_ROW)
    {

        //獲取主健的值 int型的 用 sqlite3_column_int
        int primaryKeyValueI = sqlite3_column_int(dbps, 0);
        //轉換成 NSNumber 類型的
        NSNumber *primaryKeyValue = [[NSNumber alloc]
                                     initWithInt: primaryKeyValueI];

        NSLog(@"primaryKeyValue = %@",primaryKeyValue);

        //獲取item的值 字符串用 sqlite3_column_text
        NSString *itemValue = [[NSString alloc]
                               initWithUTF8String: (char*) sqlite3_column_text (dbps, 1)];

        NSLog(@"itemValue = %@",itemValue);

        //獲取price的值  double類型用 sqlite3_column_double
        double priceValueD = sqlite3_column_double (dbps, 2);

        NSLog(@"priceValueD = %lf",priceValueD);
        //轉換類型
        NSNumber *priceValue = [[NSNumber alloc]
                                initWithDouble: priceValueD];

        NSLog(@"priceValue =  %@",priceValue);

        //獲取guoupid的值
        int groupValueI = sqlite3_column_int(dbps, 3);

        NSLog(@"groupValueI =  %d",groupValueI);

        NSNumber *groupValue = [[NSNumber alloc]
                                initWithInt: groupValueI];

        NSLog(@"groupValue =  %@",groupValue);

        //獲取dateadd的值
        NSString *dateValueS = [[NSString alloc]
                                initWithUTF8String:(char*)sqlite3_column_text (dbps, 4)];

        NSLog(@"dateValueS =  %@",dateValueS);

    }

    //10.釋放資源
    sqlite3_finalize (dbps);

    //11.關閉數據庫
    sqlite3_close(db);