Added support for ENUM in prepared statement where clause

h2/src/main/org/h2/expression/Comparison.java

@@ -16,10 +16,7 @@ import org.h2.table.Column;
 import org.h2.table.ColumnResolver;
 import org.h2.table.TableFilter;
 import org.h2.util.MathUtils;
-import org.h2.value.Value;
-import org.h2.value.ValueBoolean;
-import org.h2.value.ValueGeometry;
-import org.h2.value.ValueNull;
+import org.h2.value.*;
 
 /**
  * Example comparison expressions are ID=1, NAME=NAME, NAME IS NULL.
@@ -266,12 +263,28 @@ public class Comparison extends Condition {
             }
         }
         int dataType = Value.getHigherOrder(left.getType(), right.getType());
-        l = l.convertTo(dataType);
-        r = r.convertTo(dataType);
+        if (dataType == Value.ENUM) {
+            String[] enumerators = getEnumerators(l, r);
+            l = l.convertToEnum(enumerators);
+            r = r.convertToEnum(enumerators);
+        } else {
+            l = l.convertTo(dataType);
+            r = r.convertTo(dataType);
+        }
         boolean result = compareNotNull(database, l, r, compareType);
         return ValueBoolean.get(result);
     }
 
+    private String[] getEnumerators(Value left, Value right) {
+        if (left.getType() == Value.ENUM) {
+            return ((ValueEnum) left).getEnumerators();
+        } else if (right.getType() == Value.ENUM) {
+            return ((ValueEnum) right).getEnumerators();
+        } else {
+            return new String[0];
+        }
+    }
+
     /**
      * Compare two values, given the values are not NULL.
      *

h2/src/main/org/h2/value/Value.java

@@ -592,6 +592,17 @@ public abstract class Value {
         return convertTo(targetType, -1, null);
     }
 
+    /**
+     * Convert value to ENUM value
+     * @param enumerators allowed values for the ENUM to which the value is converted
+     * @return value represented as ENUM
+     */
+    public Value convertToEnum(String[] enumerators) {
+        // Use -1 to indicate "default behaviour" where value conversion should not
+        // depend on any datatype precision.
+        return convertTo(ENUM, -1, null, null, enumerators);
+    }
+
     /**
      * Compare a value to the specified type.
      *

h2/src/test/org/h2/test/jdbc/TestPreparedStatement.java

@@ -479,6 +479,22 @@ public class TestPreparedStatement extends TestBase {
             assertEquals(Integer.class, o.getClass());
         }
 
+        for (int i = 0; i < goodSizes.length; i++) {
+            PreparedStatement prep = conn.prepareStatement("SELECT * FROM test_enum WHERE size = ?");
+            prep.setObject(1, goodSizes[i]);
+            ResultSet rs = prep.executeQuery();
+            rs.next();
+            String s = rs.getString(1);
+            assertTrue(s.equals(goodSizes[i]));
+            assertFalse(rs.next());
+        }
+
+        for (int i = 0; i < badSizes.length; i++) {
+            PreparedStatement prep = conn.prepareStatement("SELECT * FROM test_enum WHERE size = ?");
+            prep.setObject(1, badSizes[i]);
+            assertThrows(ErrorCode.ENUM_VALUE_NOT_PERMITTED, prep).executeQuery();
+        }
+
         stat.execute("DROP TABLE test_enum");
     }