MySQL主键列不是唯一的吗？

Question

我在MySQL数据库中有下表:

CREATE TABLE `datavalues` (
  `ValueID` int(11) NOT NULL AUTO_INCREMENT,
  `DataValue` double NOT NULL,
  `ValueAccuracy` double DEFAULT NULL,
  `LocalDateTime` datetime NOT NULL,
  `UTCOffset` double NOT NULL,
  `DateTimeUTC` datetime NOT NULL,
  `SiteID` int(11) NOT NULL,
  `VariableID` int(11) NOT NULL,
  `OffsetValue` double DEFAULT NULL,
  `OffsetTypeID` int(11) DEFAULT NULL,
  `CensorCode` varchar(50) COLLATE utf8_unicode_ci NOT NULL DEFAULT 'nc',
  `QualifierID` int(11) DEFAULT NULL,
  `MethodID` int(11) NOT NULL DEFAULT '0',
  `SourceID` int(11) NOT NULL,
  `SampleID` int(11) DEFAULT NULL,
  `DerivedFromID` int(11) DEFAULT NULL,
  `QualityControlLevelID` int(11) NOT NULL DEFAULT '0',
  PRIMARY KEY (`ValueID`),
  UNIQUE KEY `DataValues_UNIQUE_DataValues`     (`DataValue`,`ValueAccuracy`,`LocalDateTime`,`UTCOffset`,`DateTimeUTC`,`SiteID`,`VariableID`,`OffsetValue`,`OffsetTypeID`,`CensorCode`,`QualifierID`,`MethodID`,`SourceID`,`SampleID`,`DerivedFromID`,`QualityControlLevelID`),
  KEY `FK_DataValues_Sites` (`SiteID`),
  KEY `FK_DataValues_Sources` (`SourceID`),
  KEY `FK_DataValues_QualityControlLevels` (`QualityControlLevelID`),
  KEY `FK_DataValues_OffsetTypes` (`OffsetTypeID`),
  KEY `FK_DataValues_CensorCodeCV` (`CensorCode`),
  KEY `FK_DataValues_Variables` (`VariableID`),
  KEY `FK_DataValues_Methods` (`MethodID`),
  KEY `FK_DataValues_Qualifiers` (`QualifierID`),
  KEY `FK_DataValues_Samples` (`SampleID`)
) ENGINE=InnoDB  DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci

ALTER TABLE `datavalues`
  ADD CONSTRAINT `FK_DataValues_Sites` FOREIGN KEY (`SiteID`) REFERENCES `sites`     (`SiteID`) ON DELETE NO ACTION ON UPDATE CASCADE,
  ADD CONSTRAINT `FK_DataValues_Sources` FOREIGN KEY (`SourceID`) REFERENCES `sources` (`SourceID`) ON DELETE NO ACTION ON UPDATE NO ACTION,
  ADD CONSTRAINT `FK_DataValues_QualityControlLevels` FOREIGN KEY (`QualityControlLevelID`) REFERENCES `qualitycontrollevels` (`QualityControlLevelID`) ON DELETE NO ACTION ON UPDATE NO ACTION,
  ADD CONSTRAINT `FK_DataValues_OffsetTypes` FOREIGN KEY (`OffsetTypeID`) REFERENCES `offsettypes` (`OffsetTypeID`) ON DELETE NO ACTION ON UPDATE NO ACTION,
  ADD CONSTRAINT `FK_DataValues_CensorCodeCV` FOREIGN KEY (`CensorCode`) REFERENCES `censorcodecv` (`Term`) ON DELETE NO ACTION ON UPDATE NO ACTION,
  ADD CONSTRAINT `FK_DataValues_Variables` FOREIGN KEY (`VariableID`) REFERENCES `variables` (`VariableID`) ON DELETE NO ACTION ON UPDATE NO ACTION,
  ADD CONSTRAINT `FK_DataValues_Methods` FOREIGN KEY (`MethodID`) REFERENCES `methods` (`MethodID`) ON DELETE NO ACTION ON UPDATE NO ACTION,
  ADD CONSTRAINT `FK_DataValues_Qualifiers` FOREIGN KEY (`QualifierID`) REFERENCES `qualifiers` (`QualifierID`) ON DELETE NO ACTION ON UPDATE NO ACTION,
  ADD CONSTRAINT `FK_DataValues_Samples` FOREIGN KEY (`SampleID`) REFERENCES `samples` (`SampleID`) ON DELETE NO ACTION ON UPDATE NO ACTION;

当我在PhpMyAdmin 4.0.3中打开我的数据库并运行查询时:

SELECT MAX(DateTimeUTC) from `datavalues` 

查询执行但PhpMyAdmin显示警告:

此表不包含唯一列.网格编辑,复选框,编辑,复制和删除功能不可用.

这怎么可能？我想如果我有一个带PRIMARY KEY约束的列,那么该列是UNIQUE.这可能是PhpMyAdmin中的错误吗？我糊涂了.

Answer 1

我找到了答案:警告:

此表不包含唯一列.网格编辑,复选框,编辑,复制和删除功能不可用.

适用于当前结果集而不适用于原始表.ÁlvaroG.Vicario的评论是对的.

这在PhpMyAdmin 4.0.4中似乎是一个新东西,我发现这种类型的消息比实用更令人困惑.