Question

虽然我已经在父表中添加了必要的信息，但我遇到了外键问题。这是模式，select语句，用于显示外键存在于父表中，以及在子表中插入新数据的错误：

MariaDB [scansmusic]＆gt; show create table chhymnal;

+----------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Table    | Create Table                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |
+----------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| chhymnal | CREATE TABLE `chhymnal` (<br>
  `CHhymnalID` int(5) unsigned NOT NULL,<br>
  `Title` varchar(30) DEFAULT NULL,<br>
  `CHNumber` int(5) unsigned DEFAULT NULL,<br>
  `Type` varchar(1) DEFAULT NULL,<br>
  `WorshipItemType` varchar(30) DEFAULT NULL,<br>
  `DateLastSung` date DEFAULT NULL,<br>
  `HighNote` varchar(5) DEFAULT NULL,<br>
  `UseThisWeek` tinyint(1) DEFAULT NULL,<br>
  `ServiceOrder` int(2) unsigned DEFAULT NULL,<br>
  `StartKey` varchar(2) DEFAULT NULL,<br>
  `EndKey` varchar(2) DEFAULT NULL,<br>
  `Tempo` int(1) unsigned DEFAULT NULL,<br>
  `TimeSig` varchar(7) DEFAULT NULL,<br>
  `CCLINumb` varchar(10) DEFAULT NULL,<br>
  PRIMARY KEY (`CHhymnalID`)<br>
) ENGINE=InnoDB DEFAULT CHARSET=latin1 |<br>
+----------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+

1行（0.00秒）

MariaDB [scansmusic]＆gt; MariaDB [scanningmusic]＆gt; show create table chimages;

+----------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Table    | Create Table                                                                                                                                                                                                                                                                                                                                       |
+----------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| <br>chimages | CREATE TABLE `chimages` (<br>
  `CHImageID` int(5) unsigned NOT NULL,<br>
  `ImagePath` varchar(50) DEFAULT NULL,<br>
  `Instrument` varchar(30) DEFAULT NULL,<br>
  `CHhymnalID` int(5) DEFAULT NULL,<br>
  PRIMARY KEY (`CHImageID`),<br>
  CONSTRAINT `fk_images` FOREIGN KEY (`CHImageID`) REFERENCES `chhymnal` (`CHhymnalID`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 |
+----------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+<br>
1 row in set (0.00 sec)
MariaDB [scannedmusic]> SELECT * FROM `chhymnal` WHERE `CHhymnalID` = 343;
+------------+-------------------------+----------+------+-----------------+--------------+----------+-------------+--------------+----------+--------+-------+---------+----------+
| CHhymnalID | Title                   | CHNumber | Type | WorshipItemType | DateLastSung | HighNote | UseThisWeek | ServiceOrder | StartKey | EndKey | Tempo | TimeSig | CCLINumb |<br>
+------------+-------------------------+----------+------+-----------------+--------------+----------+-------------+--------------+----------+--------+-------+---------+----------+
|        343 | What a Day That Will Be |      762 | h    | Hymn            | 0000-00-00   | Db       |           0 |           12 | Ab       | Ab     |     3 | 3/4     |          |
+------------+-------------------------+----------+------+-----------------+--------------+----------+-------------+--------------+----------+--------+-------+---------+----------+

1行（0.00秒）

MariaDB [scannedmusic]> INSERT INTO <br>Chimages(`CHImageID`,`ImagePath`,`CHhymnalID`) VALUES  ( 393, "\\BMP\\762_o1.bmp",343);

错误1452（23000）：无法添加或更新子行：外键约束失败（scannedmusic。chimages，CONSTRAINT fk_images 外键（CHImageID）参考chhymnal（CHhymnalID））

Answer 1

您正在查看错误的列。在表格chhymnal中，没有chhymnalid = 393行。

您的SELECT声明表明您正在检查chhymnalid chhymnal表中的chimageid，但您的外键约束适用于393值INSERT的{{1}}你的chhymnalid = 393陈述。

有两种选择 - 其中一种必须是真的：

您的意思是在创建外键约束时输入的内容，表chhymnal中没有chhymnalid行
您在外键约束中错误地引用了列名称，它应该是chimageid而不是{{1}}

1452 - 无法添加或更新子行：外键约束失败

1 个答案: