Add support for DB2 "WITH UR" clause, patch from litailang

h2/src/docsrc/html/roadmap.html

@@ -41,6 +41,7 @@ See also <a href="build.html#providing_patches">Providing Patches</a>.
 </li><li>Remove support for the old-style outer join syntax using "(+)" because it is buggy.
 </li><li>Change license to MPL 2.0.
 </li><li>Not allow relative database URLs like jdbc:h2:test; instead, require using jdbc:h2:./test.
+</li><li>Add support for DB2 "WITH UR" clause, patch from litailang
 </li></ul>
 
 <h2>Priority 1</h2>

h2/src/main/org/h2/command/Parser.java

@@ -1012,7 +1012,7 @@ public class Parser {
         }
         if (readIf("DEFAULT")) {
             read("VALUES");
-            Expression[] expr = { };
+            Expression[] expr = {};
             command.addRow(expr);
         } else if (readIf("VALUES")) {
             read("(");
@@ -1745,16 +1745,32 @@ public class Parser {
                     } while (readIf(","));
                 } else if (readIf("NOWAIT")) {
                     // TODO parser: select for update nowait: should not wait
-                } else if (readIf("WITH")) {
-                    // Hibernate / Derby support
-                    read("RR");
                 }
                 command.setForUpdate(true);
             } else if (readIf("READ") || readIf("FETCH")) {
                 read("ONLY");
+            }
+        }
+        if (database.getMode().isolationLevelInSelectStatement) {
+        	parseIsolationClause();
+        }
+    }
+
+    /**
+     * DB2 isolation clause
+     */
+    private void parseIsolationClause() {
         if (readIf("WITH")) {
-                    read("RS");
+            if (readIf("RR") || readIf("RS")) {
+                // concurrent-access-resolution clause
+                if (readIf("USE")) {
+                    read("AND");
+                    read("KEEP");
+                    if (readIf("SHARE") || readIf("UPDATE") || readIf("EXCLUSIVE")) {
+                    }
+                    read("LOCKS");
                 }
+            } else if (readIf("CS") || readIf("UR")) {
             }
         }
     }

h2/src/main/org/h2/engine/Mode.java

@@ -123,6 +123,10 @@ public class Mode {
      */
     public boolean swapConvertFunctionParameters;
 
+    /**
+     * can set the isolation level using WITH {RR|RS|CS|UR}
+     */
+    public boolean isolationLevelInSelectStatement;
 
     private final String name;
 
@@ -135,6 +139,7 @@ public class Mode {
         mode.aliasColumnName = true;
         mode.supportOffsetFetch = true;
         mode.sysDummy1 = true;
+        mode.isolationLevelInSelectStatement = true;
         add(mode);
 
         mode = new Mode("Derby");

h2/src/test/org/h2/test/db/TestCompatibility.java

@@ -374,6 +374,23 @@ public class TestCompatibility extends TestBase {
         res.next();
         assertEquals("2", res.getString(1));
         assertFalse(res.next());
+        // test isolation-clause
+        conn = getConnection("compatibility;MODE=DB2");
+        stat = conn.createStatement();
+        stat.execute("drop table test if exists");
+        stat.execute("create table test(id varchar)");
+        res = stat.executeQuery("select * from test where id = 1 with rr");
+        res = stat.executeQuery("select * from test order by id fetch next 2 rows only with rr");
+        res = stat.executeQuery("select * from test order by id fetch next 2 rows only with rs");
+        res = stat.executeQuery("select * from test order by id fetch next 2 rows only with cs");
+        res = stat.executeQuery("select * from test order by id fetch next 2 rows only with ur");
+        // test isolation-clause with lock-request-clause
+        res = stat
+                .executeQuery("select * from test order by id fetch next 2 rows only with rr use and keep share locks");
+        res = stat
+                .executeQuery("select * from test order by id fetch next 2 rows only with rs use and keep update locks");
+        res = stat
+                .executeQuery("select * from test order by id fetch next 2 rows only with rr use and keep exclusive locks");
     }
 
     private void testDerby() throws SQLException {