[METAMODEL-1137] Handle SQL server "variant" data type by casting to varchar

• Type: New Feature
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 4.5.4
• Labels: java jdbc jtds sql_variant sqlserver variant
• Environment: Windows & Linux
• Assignee: Unassigned
• Reporter: ASHISH PANCHOLI
• Created: 10/Mar/17 10:39
• Updated: 10/May/17 04:08

Description

When I am trying to run the below query:

SELECT ct."A" FROM dbo."IMAGE_TABLE1" ct

using MetaModel, it's throwing an exception:

org.apache.metamodel.MetaModelException: Could not execute query: The "variant" data type is not supported.

I completely understand that the SQL Server sqlvariant data type is not currently supported by the JDBC driver. If a query is used to retrieve data from a table that contains a column of the sqlvariant data type, an exception will occur.

But when I am casting the "sqlvariant" column to "varchar(30)" in the query then it ran successfully using jTDS ( SQL Server and Sybase JDBC driver).

Here is the (native) query that ran successfully:

SELECT CAST(A as varchar(30)) from IMAGE_TABLE1

The same I am expecting from Apache Meta model but Apache Meta model throwing a below exception:

org.apache.metamodel.query.parser.QueryParserException: Not capable of parsing SELECT token: CAST(A
	at org.apache.metamodel.query.parser.SelectItemParser.parse(SelectItemParser.java:68)
	at org.apache.metamodel.query.parser.QueryPartParser.parseItem(QueryPartParser.java:122)
	at org.apache.metamodel.query.parser.QueryPartParser.parse(QueryPartParser.java:93)
	at org.apache.metamodel.query.parser.QueryParser.parseSelectClause(QueryParser.java:160)
	at org.apache.metamodel.query.parser.QueryParser.parse(QueryParser.java:95)
	at org.apache.metamodel.AbstractDataContext.parseQuery(AbstractDataContext.java:164)
	at org.apache.metamodel.AbstractDataContext.executeQuery(AbstractDataContext.java:188)
	at org.apache.metamodel.DataContextFactoryTest.testSQLVarient(DataContextFactoryTest.java:69)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at junit.framework.TestCase.runTest(TestCase.java:176)
	at junit.framework.TestCase.runBare(TestCase.java:141)
	at junit.framework.TestResult$1.protect(TestResult.java:122)
	at junit.framework.TestResult.runProtected(TestResult.java:142)
	at junit.framework.TestResult.run(TestResult.java:125)
	at junit.framework.TestCase.run(TestCase.java:129)
	at junit.framework.TestSuite.runTest(TestSuite.java:255)
	at junit.framework.TestSuite.run(TestSuite.java:250)
	at org.junit.internal.runners.JUnit38ClassRunner.run(JUnit38ClassRunner.java:84)
	at org.junit.runner.JUnitCore.run(JUnitCore.java:160)
	at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)
	at com.intellij.rt.execution.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:51)
	at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:237)
	at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:70)

Issue Links

• links to: GitHub Pull Request #141