Handling for columns renamed in queries

Author: aguibert

vertx-db2-client/src/main/java/io/vertx/db2client/impl/DB2RowImpl.java

@@ -94,7 +94,12 @@ public int getColumnIndex(String name) {
         if (name == null) {
             throw new NullPointerException();
         }
-        return rowDesc.columnNames().indexOf(name.toUpperCase()); // DB2 column names are always in uppercase
+        int idx = rowDesc.columnIndex(name);
+        if (idx >= 0) {
+        	return idx;
+        }
+        // Unless the column is renamed in the SQL query, the column name will be uppercase
+        return rowDesc.columnIndex(name.toUpperCase());
     }
 
     @Override

vertx-db2-client/src/main/java/io/vertx/db2client/impl/codec/DB2Decoder.java

@@ -61,7 +61,9 @@ private int computeLength(ByteBuf in) {
                 dssContinues &= (in.getByte(ridx + index + 3) & 0x40) == 0x40;
             else
                 dssContinues = false;
-            short dssLen = in.getShort(ridx + index);
+            short dssLen = 11; // minimum length of DRDA message
+            if (readableBytes >= index + 2)
+            	dssLen = in.getShort(ridx + index);
             index += dssLen;
         }
         return index;

vertx-db2-client/src/main/java/io/vertx/db2client/impl/drda/ColumnMetaData.java

@@ -117,12 +117,12 @@ public List<String> getColumnNames() {
     public String getColumnName(int i) {
     	if (i < 0)
     		throw new IllegalArgumentException("Requested column name for negative index: " + i);
-    	// Prefer column names from SQLDXGRP if set
-    	if (sqlxName_ != null && i < sqlxName_.length && sqlxName_[i] != null)
-    		return sqlxName_[i];
-    	// Otherwise use column names from SQLDOPTGRP
-    	if (sqlName_ != null && i < sqlName_.length)
+    	// Prefer column names from SQLDOPTGRP if set
+    	if (sqlName_ != null && i < sqlName_.length && sqlName_[i] != null)
     		return sqlName_[i];
+    	// Otherwise use column names from SQLDXGRP
+    	if (sqlxName_ != null && i < sqlxName_.length)
+    		return sqlxName_[i];
     	return null;
     }
 

vertx-db2-client/src/main/java/io/vertx/db2client/impl/drda/DRDAQueryResponse.java

@@ -1139,7 +1139,7 @@ public void readEndOpenQuery() {
         if (peekCP == CodePoint.ENDQRYRM) {
             parseEndQuery(/*netResultSet*/);
         }
-
+        
         completeOpenQuery(sqlca);
 
         endOfSameIdChainData();
@@ -1654,6 +1654,11 @@ void parseEndQuery(/*ResultSetCallbackInterface resultSetI*/) {
         parseTypdefsOrMgrlvlovrs();
         NetSqlca netSqlca = parseSQLCARD(null);
         cursor.setAllRowsReceivedFromServer(true);
+        
+        int peekCP = peekCodePoint();
+		if (peekCP == CodePoint.RDBUPDRM) {
+			parseRDBUPDRM();
+		}
     }
 
     // Also called by NetResultSetReply subclass.

vertx-db2-client/src/test/java/io/vertx/db2client/QueryVariationsTest.java

@@ -20,6 +20,29 @@
  */
 @RunWith(VertxUnitRunner.class)
 public class QueryVariationsTest extends DB2TestBase {
+	
+	@Test
+	public void testRenamedColumns(TestContext ctx) {
+		connect(ctx.asyncAssertSuccess(conn -> {
+			conn.query("SELECT id AS THE_ID," + 
+		               "message AS \"the message\"" + 
+					"FROM immutable " +
+					"WHERE id = 10").execute(
+					ctx.asyncAssertSuccess(rowSet -> {
+				ctx.assertEquals(1, rowSet.size());
+				ctx.assertEquals(Arrays.asList("THE_ID", "the message"), rowSet.columnsNames());
+				RowIterator<Row> rows = rowSet.iterator();
+				ctx.assertTrue(rows.hasNext());
+				Row row = rows.next();
+				ctx.assertEquals(10, row.getInteger(0));
+				ctx.assertEquals(10, row.getInteger("THE_ID"));
+				ctx.assertEquals("Computers make very fast, very accurate mistakes.", row.getString(1));
+				ctx.assertEquals("Computers make very fast, very accurate mistakes.", row.getString("the message"));
+				ctx.assertFalse(rows.hasNext());
+				conn.close();
+			}));
+		}));
+	}
 
 	@Test
 	public void testSubquery(TestContext ctx) {

vertx-db2-client/src/test/java/io/vertx/db2client/TableJoinTest.java

@@ -25,19 +25,21 @@ public void testColumnRename(TestContext ctx) {
 			conn.query("SELECT immutable.id AS \"IMM ID\"," +
 		                      "immutable.message AS IMM_MSG," +
 					          "Fortune.id AS FORT_ID," +
-		                      "Fortune.message AS \"FORT ID\" FROM immutable " +
+		                      "Fortune.message AS \"fortune msg\" FROM immutable " +
             		"INNER JOIN Fortune ON (immutable.id + 1) = Fortune.id " +
 					"WHERE immutable.id=1").execute(
 					ctx.asyncAssertSuccess(rowSet -> {
 				ctx.assertEquals(1, rowSet.size());
-				// TODO This is consistent with how JDBC behaves, but we may want to add an API
-				// to retrieve column labels like JDBC has
-				ctx.assertEquals(Arrays.asList("ID", "MESSAGE", "ID", "MESSAGE"), rowSet.columnsNames());
+				ctx.assertEquals(Arrays.asList("IMM ID", "IMM_MSG", "FORT_ID", "fortune msg"), rowSet.columnsNames());
 				Row row = rowSet.iterator().next();
 				ctx.assertEquals(1, row.getInteger(0));
+				ctx.assertEquals(1, row.getInteger("IMM ID"));
 				ctx.assertEquals("fortune: No such file or directory", row.getString(1));
+				ctx.assertEquals("fortune: No such file or directory", row.getString("IMM_MSG"));
 				ctx.assertEquals(2, row.getInteger(2));
+				ctx.assertEquals(2, row.getInteger("FORT_ID"));
 				ctx.assertEquals("A computer scientist is someone who fixes things that aren't broken.", row.getString(3));
+				ctx.assertEquals("A computer scientist is someone who fixes things that aren't broken.", row.getString("fortune msg"));
 				conn.close();
 			}));
 		}));

vertx-db2-client/src/test/java/io/vertx/db2client/junit/DB2Resource.java

@@ -74,6 +74,7 @@ protected void before() throws Throwable {
 	                .setPassword(get("DB2_PASS"));
     	}
     	String jdbcUrl = "jdbc:db2://" + options.getHost() + ":" + options.getPort() + "/" + options.getDatabase();
+    	System.out.println("Initializing DB2 database at: " + jdbcUrl);
     	try (Connection con = DriverManager.getConnection(jdbcUrl, options.getUser(), options.getPassword())) {
     	  runInitSql(con);
     	}