diff --git a/asterix-app/data/csv/sample_01.csv b/asterix-app/data/csv/sample_01.csv
index a77258c..4dd437a 100644
--- a/asterix-app/data/csv/sample_01.csv
+++ b/asterix-app/data/csv/sample_01.csv
@@ -1,4 +1,8 @@
 1,0.899682764,5.6256,2013-08-07,07:22:35,1979-02-25T23:48:27.034
 2,0.669052398,,-1923-03-29,19:33:34,-1979-02-25T23:48:27.002
-,,,,,,,,,,
-3,0.572733058,192674,-1923-03-29,19:33:34,-1979-02-25T23:48:27.001
\ No newline at end of file
+3,0.572733058,192674,-1923-03-28,19:33:34,-1979-02-25T23:48:27.001
+4,,192674,-1923-03-27,19:33:34,-1979-02-25T23:48:27.001
+5,0.572733058,192674,,19:33:34,-1979-02-25T23:48:27.001
+6,0.572733058,192674,-1923-03-25,,-1979-02-25T23:48:27.001
+7,0.572733058,192674,-1923-03-24,19:33:34,
+8,,,,,
\ No newline at end of file
diff --git a/asterix-app/src/test/resources/runtimets/queries/load/csv_01/csv_01.1.ddl.aql b/asterix-app/src/test/resources/runtimets/queries/load/csv_01/csv_01.1.ddl.aql
index 7a0e4b0..e890942 100644
--- a/asterix-app/src/test/resources/runtimets/queries/load/csv_01/csv_01.1.ddl.aql
+++ b/asterix-app/src/test/resources/runtimets/queries/load/csv_01/csv_01.1.ddl.aql
@@ -10,12 +10,12 @@
 use dataverse temp;
 
 create type test as closed {
-    id: string,
-    float: string,
-    double: string,
-    date: string,
-    time: string,
-    datetime: string
+    id: int32,
+    float: float?,
+    double: double?,
+    date: string?,
+    time: string?,
+    datetime: string?
 };
 
 create dataset testds (test)
diff --git a/asterix-app/src/test/resources/runtimets/queries/load/csv_01/csv_01.3.query.aql b/asterix-app/src/test/resources/runtimets/queries/load/csv_01/csv_01.3.query.aql
index f798b20..efa6dbc 100644
--- a/asterix-app/src/test/resources/runtimets/queries/load/csv_01/csv_01.3.query.aql
+++ b/asterix-app/src/test/resources/runtimets/queries/load/csv_01/csv_01.3.query.aql
@@ -8,10 +8,11 @@
 use dataverse temp;
 
 for $i in dataset testds
+order by $i.id
 return { "id": $i.id, 
          "float": $i.float, 
          "double": $i.double, 
-         "date": date($i.date), 
-         "time": time($i.time),
-         "datetime": datetime($i.datetime)
+         "date-before": $i.date, "date-after": date($i.date), 
+         "time-before": $i.time, "time-after": time($i.time),
+         "datetime-before": $i.datetime, "datetime-after": datetime($i.datetime)
          }
\ No newline at end of file
diff --git a/asterix-app/src/test/resources/runtimets/queries/load/csv_02/csv_02.1.ddl.aql b/asterix-app/src/test/resources/runtimets/queries/load/csv_02/csv_02.1.ddl.aql
new file mode 100644
index 0000000..b6884a8
--- /dev/null
+++ b/asterix-app/src/test/resources/runtimets/queries/load/csv_02/csv_02.1.ddl.aql
@@ -0,0 +1,22 @@
+/**
+ *
+ * CSV file loading test
+ * Expected result: success
+ *
+ */
+ 
+drop dataverse temp if exists;
+create dataverse temp
+use dataverse temp;
+
+create type test as closed {
+    id: int32,
+    float: float?,
+    double: double?,
+    date: string,
+    time: string,
+    datetime: string
+};
+
+create dataset testds (test)
+primary key id;
diff --git a/asterix-app/src/test/resources/runtimets/queries/load/csv_02/csv_02.2.update.aql b/asterix-app/src/test/resources/runtimets/queries/load/csv_02/csv_02.2.update.aql
new file mode 100644
index 0000000..c3161d5
--- /dev/null
+++ b/asterix-app/src/test/resources/runtimets/queries/load/csv_02/csv_02.2.update.aql
@@ -0,0 +1,12 @@
+/**
+ *
+ * CSV file loading test
+ * Expected result: success
+ *
+ */
+
+use dataverse temp;
+
+load dataset testds
+using "edu.uci.ics.asterix.external.dataset.adapter.NCFileSystemAdapter"
+(("path"="nc1://data/csv/sample_01.csv"),("format"="delimited-text"),("delimiter"=","));
\ No newline at end of file
diff --git a/asterix-app/src/test/resources/runtimets/queries/load/csv_02/csv_02.3.query.aql b/asterix-app/src/test/resources/runtimets/queries/load/csv_02/csv_02.3.query.aql
new file mode 100644
index 0000000..1299235
--- /dev/null
+++ b/asterix-app/src/test/resources/runtimets/queries/load/csv_02/csv_02.3.query.aql
@@ -0,0 +1,18 @@
+/**
+ *
+ * CSV file loading test
+ * Expected result: success
+ *
+ */
+
+use dataverse temp;
+
+for $i in dataset testds
+order by $i.id
+return { "id": $i.id, 
+         "float": $i.float, 
+         "double": $i.double, 
+         "date-string": $i.date, 
+         "time-string": $i.time,
+         "datetime-string": $i.datetime
+         }
\ No newline at end of file
diff --git a/asterix-app/src/test/resources/runtimets/results/load/csv_01/csv_01.1.adm b/asterix-app/src/test/resources/runtimets/results/load/csv_01/csv_01.1.adm
index 1e28c78..b8d4151 100644
--- a/asterix-app/src/test/resources/runtimets/results/load/csv_01/csv_01.1.adm
+++ b/asterix-app/src/test/resources/runtimets/results/load/csv_01/csv_01.1.adm
@@ -1,3 +1,8 @@
-{ "id": "1", "float": "0.899682764", "double": "5.6256", "date": date("2013-08-07"), "time": time("07:22:35.000Z"), "datetime": datetime("1979-02-25T23:48:27.034Z") }
-{ "id": "3", "float": "0.572733058", "double": "192674", "date": date("-1923-03-29"), "time": time("19:33:34.000Z"), "datetime": datetime("-1979-02-25T23:48:27.001Z") }
-{ "id": "2", "float": "0.669052398", "double": "", "date": date("-1923-03-29"), "time": time("19:33:34.000Z"), "datetime": datetime("-1979-02-25T23:48:27.002Z") }
\ No newline at end of file
+{ "id": 1, "float": 0.89968276f, "double": 5.6256d, "date-before": "2013-08-07", "date-after": date("2013-08-07"), "time-before": "07:22:35", "time-after": time("07:22:35.000Z"), "datetime-before": "1979-02-25T23:48:27.034", "datetime-after": datetime("1979-02-25T23:48:27.034Z") }
+{ "id": 2, "float": 0.6690524f, "double": null, "date-before": "-1923-03-29", "date-after": date("-1923-03-29"), "time-before": "19:33:34", "time-after": time("19:33:34.000Z"), "datetime-before": "-1979-02-25T23:48:27.002", "datetime-after": datetime("-1979-02-25T23:48:27.002Z") }
+{ "id": 3, "float": 0.57273304f, "double": 192674.0d, "date-before": "-1923-03-28", "date-after": date("-1923-03-28"), "time-before": "19:33:34", "time-after": time("19:33:34.000Z"), "datetime-before": "-1979-02-25T23:48:27.001", "datetime-after": datetime("-1979-02-25T23:48:27.001Z") }
+{ "id": 4, "float": null, "double": 192674.0d, "date-before": "-1923-03-27", "date-after": date("-1923-03-27"), "time-before": "19:33:34", "time-after": time("19:33:34.000Z"), "datetime-before": "-1979-02-25T23:48:27.001", "datetime-after": datetime("-1979-02-25T23:48:27.001Z") }
+{ "id": 5, "float": 0.57273304f, "double": 192674.0d, "date-before": null, "date-after": null, "time-before": "19:33:34", "time-after": time("19:33:34.000Z"), "datetime-before": "-1979-02-25T23:48:27.001", "datetime-after": datetime("-1979-02-25T23:48:27.001Z") }
+{ "id": 6, "float": 0.57273304f, "double": 192674.0d, "date-before": "-1923-03-25", "date-after": date("-1923-03-25"), "time-before": null, "time-after": null, "datetime-before": "-1979-02-25T23:48:27.001", "datetime-after": datetime("-1979-02-25T23:48:27.001Z") }
+{ "id": 7, "float": 0.57273304f, "double": 192674.0d, "date-before": "-1923-03-24", "date-after": date("-1923-03-24"), "time-before": "19:33:34", "time-after": time("19:33:34.000Z"), "datetime-before": null, "datetime-after": null }
+{ "id": 8, "float": null, "double": null, "date-before": null, "date-after": null, "time-before": null, "time-after": null, "datetime-before": null, "datetime-after": null }
\ No newline at end of file
diff --git a/asterix-app/src/test/resources/runtimets/results/load/csv_02/csv_02.1.adm b/asterix-app/src/test/resources/runtimets/results/load/csv_02/csv_02.1.adm
new file mode 100644
index 0000000..44240dd
--- /dev/null
+++ b/asterix-app/src/test/resources/runtimets/results/load/csv_02/csv_02.1.adm
@@ -0,0 +1,8 @@
+{ "id": 1, "float": 0.89968276f, "double": 5.6256d, "date-string": "2013-08-07", "time-string": "07:22:35", "datetime-string": "1979-02-25T23:48:27.034" }
+{ "id": 2, "float": 0.6690524f, "double": null, "date-string": "-1923-03-29", "time-string": "19:33:34", "datetime-string": "-1979-02-25T23:48:27.002" }
+{ "id": 3, "float": 0.57273304f, "double": 192674.0d, "date-string": "-1923-03-28", "time-string": "19:33:34", "datetime-string": "-1979-02-25T23:48:27.001" }
+{ "id": 4, "float": null, "double": 192674.0d, "date-string": "-1923-03-27", "time-string": "19:33:34", "datetime-string": "-1979-02-25T23:48:27.001" }
+{ "id": 5, "float": 0.57273304f, "double": 192674.0d, "date-string": "", "time-string": "19:33:34", "datetime-string": "-1979-02-25T23:48:27.001" }
+{ "id": 6, "float": 0.57273304f, "double": 192674.0d, "date-string": "-1923-03-25", "time-string": "", "datetime-string": "-1979-02-25T23:48:27.001" }
+{ "id": 7, "float": 0.57273304f, "double": 192674.0d, "date-string": "-1923-03-24", "time-string": "19:33:34", "datetime-string": "" }
+{ "id": 8, "float": null, "double": null, "date-string": "", "time-string": "", "datetime-string": "" }
\ No newline at end of file
diff --git a/asterix-app/src/test/resources/runtimets/testsuite.xml b/asterix-app/src/test/resources/runtimets/testsuite.xml
index 1ec46dc..d65da69 100644
--- a/asterix-app/src/test/resources/runtimets/testsuite.xml
+++ b/asterix-app/src/test/resources/runtimets/testsuite.xml
@@ -4258,6 +4258,11 @@
       </compilation-unit>
     </test-case>
     <test-case FilePath="load">
+      <compilation-unit name="csv_02">
+        <output-dir compare="Text">csv_02</output-dir>
+      </compilation-unit>
+    </test-case>
+    <test-case FilePath="load">
       <compilation-unit name="issue14_query">
         <output-dir compare="Text">none</output-dir>
         <expected-error>edu.uci.ics.asterix.common.exceptions.AsterixException</expected-error> 
diff --git a/asterix-external-data/src/main/java/edu/uci/ics/asterix/external/dataset/adapter/FileSystemBasedAdapter.java b/asterix-external-data/src/main/java/edu/uci/ics/asterix/external/dataset/adapter/FileSystemBasedAdapter.java
index 38903ec..33ee11f 100644
--- a/asterix-external-data/src/main/java/edu/uci/ics/asterix/external/dataset/adapter/FileSystemBasedAdapter.java
+++ b/asterix-external-data/src/main/java/edu/uci/ics/asterix/external/dataset/adapter/FileSystemBasedAdapter.java
@@ -16,6 +16,7 @@
 
 import java.io.IOException;
 import java.io.InputStream;
+import java.util.List;
 import java.util.Map;
 import java.util.logging.Level;
 import java.util.logging.Logger;
@@ -26,6 +27,7 @@
 import edu.uci.ics.asterix.external.util.INodeResolverFactory;
 import edu.uci.ics.asterix.om.types.ARecordType;
 import edu.uci.ics.asterix.om.types.ATypeTag;
+import edu.uci.ics.asterix.om.types.AUnionType;
 import edu.uci.ics.asterix.om.types.IAType;
 import edu.uci.ics.asterix.runtime.operators.file.AdmSchemafullRecordParserFactory;
 import edu.uci.ics.asterix.runtime.operators.file.NtDelimitedDataTupleParserFactory;
@@ -89,7 +91,7 @@
                 throw new IllegalArgumentException(" Unspecified data format");
             } else if (FORMAT_DELIMITED_TEXT.equalsIgnoreCase(specifiedFormat)) {
                 parserFactory = getDelimitedDataTupleParserFactory((ARecordType) atype);
-            } else if (FORMAT_ADM.equalsIgnoreCase((String)configuration.get(KEY_FORMAT))) {
+            } else if (FORMAT_ADM.equalsIgnoreCase((String) configuration.get(KEY_FORMAT))) {
                 parserFactory = getADMDataTupleParserFactory((ARecordType) atype);
             } else {
                 throw new IllegalArgumentException(" format " + configuration.get(KEY_FORMAT) + " not supported");
@@ -104,7 +106,19 @@
         int n = recordType.getFieldTypes().length;
         IValueParserFactory[] fieldParserFactories = new IValueParserFactory[n];
         for (int i = 0; i < n; i++) {
-            ATypeTag tag = recordType.getFieldTypes()[i].getTypeTag();
+            ATypeTag tag = null;
+            if (recordType.getFieldTypes()[i].getTypeTag() == ATypeTag.UNION) {
+                List<IAType> unionTypes = ((AUnionType) recordType.getFieldTypes()[i]).getUnionList();
+                if (unionTypes.size() != 2 && unionTypes.get(0).getTypeTag() != ATypeTag.NULL) {
+                    throw new NotImplementedException("Non-optional UNION type is not supported.");
+                }
+                tag = unionTypes.get(1).getTypeTag();
+            } else {
+                tag = recordType.getFieldTypes()[i].getTypeTag();
+            }
+            if (tag == null) {
+                throw new NotImplementedException("Failed to get the type information for field " + i + ".");
+            }
             IValueParserFactory vpf = typeToValueParserFactMap.get(tag);
             if (vpf == null) {
                 throw new NotImplementedException("No value parser factory for delimited fields of type " + tag);
diff --git a/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/evaluators/constructors/ADateConstructorDescriptor.java b/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/evaluators/constructors/ADateConstructorDescriptor.java
index 03c4140..f13f39c 100644
--- a/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/evaluators/constructors/ADateConstructorDescriptor.java
+++ b/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/evaluators/constructors/ADateConstructorDescriptor.java
@@ -83,6 +83,13 @@
 
                                 int stringLength = (serString[1] & 0xff << 8) + (serString[2] & 0xff << 0);
 
+                                // the string to be parsed should be at least 14 characters: YYYYMMDD
+                                if (stringLength < 8) {
+                                    throw new AlgebricksException(errorMessage
+                                            + ": the string length should be at least 8 (YYYYMMDD) but it is "
+                                            + stringLength);
+                                }
+
                                 int startOffset = 3;
                                 while (serString[startOffset] == ' ') {
                                     startOffset++;
@@ -111,8 +118,6 @@
                             }
                         } catch (IOException e1) {
                             throw new AlgebricksException(errorMessage);
-                        } catch (Exception e2) {
-                            throw new AlgebricksException(e2);
                         }
                     }
                 };
diff --git a/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/evaluators/constructors/ADateTimeConstructorDescriptor.java b/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/evaluators/constructors/ADateTimeConstructorDescriptor.java
index 986b158..880de44 100644
--- a/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/evaluators/constructors/ADateTimeConstructorDescriptor.java
+++ b/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/evaluators/constructors/ADateTimeConstructorDescriptor.java
@@ -82,7 +82,12 @@
                             if (serString[0] == SER_STRING_TYPE_TAG) {
 
                                 int stringLength = (serString[1] & 0xff << 8) + (serString[2] & 0xff << 0);
-
+                                // the string to be parsed should be at least 14 characters: YYYYMMDDhhmmss
+                                if (stringLength < 14) {
+                                    throw new AlgebricksException(errorMessage
+                                            + ": the string length should be at least 14 (YYYYMMDDhhmmss) but it is "
+                                            + stringLength);
+                                }
                                 // +1 if it is negative (-)
                                 short timeOffset = (short) ((serString[3] == '-') ? 1 : 0);
 
@@ -109,8 +114,6 @@
                             }
                         } catch (IOException e1) {
                             throw new AlgebricksException(errorMessage);
-                        } catch (Exception e2) {
-                            throw new AlgebricksException(e2);
                         }
                     }
                 };
diff --git a/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/evaluators/constructors/ATimeConstructorDescriptor.java b/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/evaluators/constructors/ATimeConstructorDescriptor.java
index 1b3e7f6..d344d1c 100644
--- a/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/evaluators/constructors/ATimeConstructorDescriptor.java
+++ b/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/evaluators/constructors/ATimeConstructorDescriptor.java
@@ -83,6 +83,13 @@
 
                                 int stringLength = (serString[1] & 0xff << 8) + (serString[2] & 0xff << 0);
 
+                                // the string to be parsed should be at least 6 characters: hhmmss
+                                if (stringLength < 6) {
+                                    throw new AlgebricksException(errorMessage
+                                            + ": the string length should be at least 6 (hhmmss) but it is "
+                                            + stringLength);
+                                }
+
                                 int chrononTimeInMs = ATimeParserFactory.parseTimePart(serString, 3, stringLength);
 
                                 if (chrononTimeInMs < 0) {
@@ -99,8 +106,6 @@
                             }
                         } catch (IOException e1) {
                             throw new AlgebricksException(errorMessage);
-                        } catch (Exception e2) {
-                            throw new AlgebricksException(e2);
                         }
                     }
                 };
diff --git a/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/operators/file/DelimitedDataParser.java b/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/operators/file/DelimitedDataParser.java
index 85242ec..5a639dc 100644
--- a/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/operators/file/DelimitedDataParser.java
+++ b/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/operators/file/DelimitedDataParser.java
@@ -24,7 +24,9 @@
 import edu.uci.ics.asterix.builders.IARecordBuilder;
 import edu.uci.ics.asterix.builders.RecordBuilder;
 import edu.uci.ics.asterix.common.exceptions.AsterixException;
+import edu.uci.ics.asterix.dataflow.data.nontagged.serde.ANullSerializerDeserializer;
 import edu.uci.ics.asterix.om.base.AMutableString;
+import edu.uci.ics.asterix.om.base.ANull;
 import edu.uci.ics.asterix.om.types.ARecordType;
 import edu.uci.ics.asterix.om.types.ATypeTag;
 import edu.uci.ics.hyracks.api.exceptions.HyracksDataException;
@@ -109,17 +111,27 @@
                 }
                 fieldValueBuffer.reset();
 
-                if (cursor.fStart != cursor.fEnd) {
+                if (cursor.fStart == cursor.fEnd && recordType.getFieldTypes()[i].getTypeTag() != ATypeTag.STRING
+                        && recordType.getFieldTypes()[i].getTypeTag() != ATypeTag.NULL) {
+                    // if the field is empty and the type is optional, insert NULL
+                    // note that string type can also process empty field as an empty string
+                    if (recordType.getFieldTypes()[i].getTypeTag() != ATypeTag.UNION) {
+                        throw new AsterixException("Field " + i + " cannot be NULL. ");
+                    }
+                    fieldValueBufferOutput.writeByte(ATypeTag.NULL.serialize());
+                    ANullSerializerDeserializer.INSTANCE.serialize(ANull.NULL, out);
+                } else {
+                    fieldValueBufferOutput.writeByte(fieldTypeTags[i]);
+                    valueParsers[i].parse(cursor.buffer, cursor.fStart, cursor.fEnd - cursor.fStart,
+                            fieldValueBufferOutput);
                     areAllNullFields = false;
                 }
-                fieldValueBufferOutput.writeByte(fieldTypeTags[i]);
-                valueParsers[i]
-                        .parse(cursor.buffer, cursor.fStart, cursor.fEnd - cursor.fStart, fieldValueBufferOutput);
                 if (fldIds[i] < 0) {
                     recBuilder.addField(nameBuffers[i], fieldValueBuffer);
                 } else {
                     recBuilder.addField(fldIds[i], fieldValueBuffer);
                 }
+
             }
             if (!areAllNullFields) {
                 recBuilder.write(out, true);