引用其自己的列别名的查询的 UCanAccess“找不到对象”错误

Posted 2023-04-19

【中文标题】引用其自己的列别名的查询的 UCanAccess“找不到对象”错误

【英文标题】：UCanAccess "object not found" error for query that references its own column alias

【发布时间】：2015-08-19 13:31:05

【问题描述】：

由于 JAVA 8 不再支持 JDBC:ODBC 桥，我尝试将其替换为 Ucanaccess V3.0，但我遇到了一些问题，请参阅以下内容。

这是我用来连接数据库的代码：

String url = "jdbc:ucanaccess://D:/ADEL/ADEL Local/ADEL_DATA.accdb";
        try
        
            //Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
            Class.forName("net.ucanaccess.jdbc.UcanaccessDriver");

        
        catch (java.lang.ClassNotFoundException e)
        
            System.err.print("ClassNotFoundException: ");
            System.err.println(e.getMessage());
            ErrorFile.writeError(Thread.currentThread().getStackTrace()[2].getLineNumber(), e);
        

要运行查询，我使用之前使用 JDBC:ODBC 的相同代码

Connection c = ConnectDB.doConnect();

String selectString = "SELECT DISTINCT [Maintenance input Check Due List].[Interval (Mos)], [Maintenance input Check Due List].InputAircraftHours, [Maintenance input Check Due List].InputAircraftLandings,  [Maintenance input Check Due List].Check, [Maintenance input Check Due List].Title, [Maintenance input Check Due List].InputNumber, [Maintenance input Check Due List].AircraftCurrentTSN, [Maintenance input Check Due List].AircraftCurrentCSN, [Maintenance input Check Due List].Aircraft, [Maintenance input Check Due List].InputDateOUT, [Maintenance input Check Due List].[Interval (Hrs)], [Maintenance input Check Due List].[Interval(Ldgs)], [Maintenance input Check Due List].[NextDueCheckMonth], [Maintenance input Check Due List].NextDueCheckHours, [Maintenance input Check Due List].NextDueCheckLdgs, [Maintenance input Check Due List].RemainCheckMonth, [Maintenance input Check Due List].RemainCheckHours,[Maintenance input Check Due List].RemainCheckLdgs,[Maintenance input Check Due List].InputRepairStation,[Maintenance input Check Due List].InputDescription "
            + "FROM [Maintenance input table] RIGHT JOIN ([Maintenance Schedule Check] RIGHT JOIN   [...]

try
    
        stmt = c.createStatement();
        ResultSet data = stmt.executeQuery(selectString);
        System.out.print("(AircraftDueList-ln539) " + "requete passed\n");
        while (data.next())
        [...]

catch (SQLException e)
    
        ErrorFile.writeError(Thread.currentThread().getStackTrace()[2].getLineNumber(), e);
        System.err.println("SQLException: "
                + e.getMessage());
        e.printStackTrace();
    

但是这个查询抛出异常：

 SQLException: UCAExc:::3.0.0 user lacks privilege or object not found: NEXTDUECHECKMONTH
net.ucanaccess.jdbc.UcanaccessSQLException: UCAExc:::3.0.0 user lacks privilege or object not found: NEXTDUECHECKMONTH
at     net.ucanaccess.jdbc.UcanaccessStatement.executeQuery(UcanaccessStatement.java:211)
at main.AircraftDueList.inspPack(AircraftDueList.java:626)
at main.AircraftDueList.createPDF(AircraftDueList.java:88)
at main.AircraftList.<init>(AircraftList.java:166)
at Launch.main(Launch.java:13)
Caused by: java.sql.SQLSyntaxErrorException: user lacks privilege or object not found: NEXTDUECHECKMONTH
at org.hsqldb.jdbc.JDBCUtil.sqlException(Unknown Source)
at org.hsqldb.jdbc.JDBCUtil.sqlException(Unknown Source)
at org.hsqldb.jdbc.JDBCStatement.fetchResult(Unknown Source)
at org.hsqldb.jdbc.JDBCStatement.executeQuery(Unknown Source)
at net.ucanaccess.jdbc.UcanaccessStatement.executeQuery(UcanaccessStatement.java:208)
... 4 more
Caused by: org.hsqldb.HsqlException: user lacks privilege or object not found: NEXTDUECHECKMONTH
at org.hsqldb.error.Error.error(Unknown Source)
at org.hsqldb.error.Error.error(Unknown Source)
at org.hsqldb.ExpressionColumn.checkColumnsResolved(Unknown Source)
at org.hsqldb.RangeVariable.resolveRangeTable(Unknown Source)
at org.hsqldb.QuerySpecification.resolveRangeVariables(Unknown Source)
at org.hsqldb.QuerySpecification.resolveReferences(Unknown Source)
at org.hsqldb.ParserDQL.XreadJoinedTableAsSubqueryOrNull(Unknown Source)
at org.hsqldb.ParserDQL.readTableOrSubquery(Unknown Source)
at org.hsqldb.ParserDQL.XreadTableReference(Unknown Source)
at org.hsqldb.ParserDQL.XreadFromClause(Unknown Source)
at org.hsqldb.ParserDQL.XreadTableExpression(Unknown Source)
at org.hsqldb.ParserDQL.XreadQuerySpecification(Unknown Source)
at org.hsqldb.ParserDQL.XreadSimpleTable(Unknown Source)
at org.hsqldb.ParserDQL.XreadQueryPrimary(Unknown Source)
at org.hsqldb.ParserDQL.XreadQueryTerm(Unknown Source)
at org.hsqldb.ParserDQL.XreadQueryExpressionBody(Unknown Source)
at org.hsqldb.ParserDQL.XreadQueryExpression(Unknown Source)
at org.hsqldb.ParserDQL.compileCursorSpecification(Unknown Source)
at org.hsqldb.ParserCommand.compilePart(Unknown Source)
at org.hsqldb.ParserCommand.compileStatements(Unknown Source)
at org.hsqldb.Session.executeDirectStatement(Unknown Source)
at org.hsqldb.Session.execute(Unknown Source)
... 7 more

此查询调用表和访问中的存储查询，“NEXTDUECHECKMONTH”是访问中名为“[维护输入检查到期清单]”的存储查询的别名字段。

在存储的查询 [Maintenance input Check Due List] 中，字段 NEXTDUECHECKMONTH 的结构如下：

IIf([Interval (Mos)] Is Null,Null,DateAdd("m",[Interval (Mos)],[InputDateOUT])) AS NextDueCheckMonth

有人成功解决过这类问题吗？

PS : 我的所有查询都在 ACCESS 中成功运行

【问题讨论】：

请edit 向我们展示产生错误的minimal reproducible example 的Java 代码。我无法在保存的查询上使用简单的 SELECT 语句重新创建您的问题。

我试图改进我的帖子，我认为过去的查询不是很有帮助，因为它是一个大而令人困惑的查询。

【参考方案1】：

正如对另一个答案的评论中提到的，问题是查询有一个 WHERE 子句试图引用在同一查询中定义的列别名。这在 UCanAccess 中不起作用，例如，

sql = 
        "SELECT Date1 AS DateAlias " +
        "FROM DateTest " +
        "WHERE DateAlias IS NOT NULL";

抛出

net.ucanaccess.jdbc.UcanaccessSQLException: UCAExc:::3.0.0 用户缺少权限或找不到对象：DATEALIAS

但它在 Access 本身中也不起作用，因为 Access 不会将别名识别为列名，因此会提示我们输入参数值：

解决此问题的一种方法是将原始查询封装为子查询，以便外部查询可以使用别名：

sql = 
        "SELECT DateAlias " +
        "FROM (SELECT Date1 AS DateAlias FROM DateTest) " +
        "WHERE DateAlias IS NOT NULL";

【参考方案2】：

我发现了问题：我尝试在查询中创建别名并在此查询中使用它们； Ucanaccess 不喜欢它。

【讨论】：

您是在谈论查询的 FROM 子句中的表别名，例如，... FROM ... RIGHT JOIN [Maintenance input Check Due List] AS micdl ...？如果是这样，那么您还需要在列列表 (SELECT ...) 中使用表别名（而不是表/查询名称）。

我说的是一个行别名：在这个查询中我有IIf([Interval (Mos)] Is Null,Null,DateAdd("m",[Interval (Mos)],[InputDateOUT])) AS NextDueCheckMonth，但是在有像WHERE NextDueCheckMonth = ...这样的条件之后的一些行来解决这个问题我用WHERE IIf([Interval (Mos)] Is Null,Null,DateAdd("m",[Interval (Mos)],[InputDateOUT])) = ...替换它