[ADQL] Put column aliases in lower case while translating into SQL

if the alias is not delimited in ADQL.

This commit fixes the GitHub issue #56

src/adql/query/ADQLQuery.java

@@ -47,7 +47,7 @@ import adql.search.ISearchHandler;
  * <p>The resulting object of the {@link ADQLParser} is an object of this class.</p>
  *
  * @author Gr&eacute;gory Mantelet (CDS;ARI)
- * @version 1.4 (04/2017)
+ * @version 1.4 (11/2017)
  */
 public class ADQLQuery implements ADQLObject {
 
@@ -324,11 +324,20 @@ public class ADQLQuery implements ADQLObject {
 				DBColumn col = null;
 				// ...whose the name will be set with the SELECT item's alias:
 				if (item.hasAlias()){
+					// put the alias in lower case if not written between "":
+					/* Note: This aims to avoid unexpected behavior at execution
+					 *       time in the DBMS (i.e. the case sensitivity is
+					 *       forced for every references to this column alias). */
+					String alias = item.getAlias();
+					if (!item.isCaseSensitive())
+						alias = alias.toLowerCase();
+
+					// create the DBColumn:
 					if (operand instanceof ADQLColumn && ((ADQLColumn)operand).getDBLink() != null){
 						col = ((ADQLColumn)operand).getDBLink();
-						col = col.copy(col.getDBName(), item.getAlias(), col.getTable());
+						col = col.copy(col.getDBName(), alias, col.getTable());
 					}else
-						col = new DefaultDBColumn(item.getAlias(), null);
+						col = new DefaultDBColumn(alias, null);
 				}
 				// ...or whose the name will be the name of the SELECT item:
 				else{

src/adql/translator/JDBCTranslator.java

@@ -443,7 +443,10 @@ public abstract class JDBCTranslator implements ADQLTranslator {
 		StringBuffer translation = new StringBuffer(translate(item.getOperand()));
 		if (item.hasAlias()){
 			translation.append(" AS ");
-			appendIdentifier(translation, item.getAlias(), item.isCaseSensitive());
+			if (item.isCaseSensitive())
+				appendIdentifier(translation, item.getAlias(), true);
+			else
+				appendIdentifier(translation, item.getAlias().toLowerCase(), true);
 		}else{
 			translation.append(" AS ");
 			appendIdentifier(translation, item.getName(), true);

test/adql/db/TestSubQueries.java

@@ -55,7 +55,6 @@ public class TestSubQueries {
 			ADQLParser adqlParser = new ADQLParser(new DBChecker(esaTables));
 
 			ADQLQuery query = adqlParser.parseQuery("SELECT oid FROM table1 as MyAlias WHERE oid IN (SELECT oid2 FROM table2 WHERE oid2 = myAlias.oid)");
-			System.out.println((new PostgreSQLTranslator()).translate(query));
 			assertEquals("SELECT \"myalias\".\"oid\" AS \"oid\"\nFROM \"public\".\"table1\" AS \"myalias\"\nWHERE \"myalias\".\"oid\" IN (SELECT \"public\".\"table2\".\"oid2\" AS \"oid2\"\nFROM \"public\".\"table2\"\nWHERE \"public\".\"table2\".\"oid2\" = \"myalias\".\"oid\")", (new PostgreSQLTranslator()).translate(query));
 		}catch(Exception ex){
 			ex.printStackTrace(System.err);
@@ -63,4 +62,24 @@ public class TestSubQueries {
 		}
 	}
 
+	@Test
+	public void testParentRefToMixedCaseColumnAliasInsideSubQueries(){
+		try{
+			TableSetParser tsParser = new TableSetParser();
+			TAPMetadata esaMetaData = tsParser.parse(new File("test/adql/db/subquery_test_tables.xml"));
+			ArrayList<DBTable> esaTables = new ArrayList<DBTable>(esaMetaData.getNbTables());
+			Iterator<TAPTable> itTables = esaMetaData.getTables();
+			while(itTables.hasNext())
+				esaTables.add(itTables.next());
+
+			ADQLParser adqlParser = new ADQLParser(new DBChecker(esaTables));
+
+			ADQLQuery query = adqlParser.parseQuery("SELECT t.* FROM (SELECT (ra+ra_error) AS x, (dec+dec_error) AS Y, pmra AS \"ProperMotion\" FROM table2) AS t");
+			assertEquals("SELECT \"t\".\"x\" AS \"x\",\"t\".\"y\" AS \"y\",\"t\".\"ProperMotion\" AS \"ProperMotion\"\nFROM (SELECT (\"public\".\"table2\".\"ra\"+\"public\".\"table2\".\"ra_error\") AS \"x\" , (\"public\".\"table2\".\"dec\"+\"public\".\"table2\".\"dec_error\") AS \"y\" , \"public\".\"table2\".\"pmra\" AS \"ProperMotion\"\nFROM \"public\".\"table2\") AS \"t\"", (new PostgreSQLTranslator()).translate(query));
+		}catch(Exception ex){
+			ex.printStackTrace(System.err);
+			fail("No error expected! (see console for more details)");
+		}
+	}
+
 }