How to store Date and Time in separate columns in SQL Server 2005

In this article I will explain how to store Date and Time in SQL Server 2005 using User Defined Type

Introduction

In SQL Server 2008 four new data types were added. Two of them are Date and Time for storing date and time as separate data types. But if you need to deal with separate Date and Time in SQL Server 2005, either you store Date in DateTime and parse its date and time part or store date and time in a string data type.

Other alternative is to create User Defined Data Type (UDT) for storing Date and Time. So here we will create two UDT and then we will use these User Defined Data Types in table columns. Then we will add CHECK CONSTRAINT on the columns to ensure only valid data is inserted in these columns.

Step 1: Create User Defined Data Types

CREATE TYPE Date
FROM VARCHAR(10) NOT NULL

CREATE TYPE Time
FROM VARCHAR(8) NOT NULL

Here we have created two User Defined Data Types Date and time based on VARCHAR data type.

Step 2: Create Table

Create a table named ‘Student’ and define its ‘DateOfBirth’ and ‘TimeOfBirth’ columns with Date and Time UDT respectively.

Step 3: Add Functions for validation

CREATE FUNCTION ValidateDate(@Date VARCHAR(10))
RETURNS INTEGER
AS
BEGIN
     DECLARE @ReturnValue INT
     DECLARE @DD VARCHAR(2)
     DECLARE @MM VARCHAR(2)
     DECLARE @YYYY VARCHAR(4)
     IF(@Date LIKE'[0-3][0-9]/[0-1][0-9]/[0-9][0-9][0-9][0-9]')
          BEGIN
               SET @DD=SUBSTRING(@Date, 1, 2)
               SET @MM=SUBSTRING(@Date, 4, 2)
               SET @YYYY=SUBSTRING(@Date, 7, 4)
               SET @ReturnValue=ISDATE(@MM+'/'+@DD+'/'+@YYYY)
          END
     ELSE
          SET @ReturnValue=0
     RETURN @ReturnValue
END

CREATE FUNCTION ValidateTime(@Time VARCHAR(8))
RETURNS INTEGER
AS
BEGIN
     DECLARE @ReturnValue INTEGER
     DECLARE @HH INT
     DECLARE @MM INT
     DECLARE @SS INT
     IF(@Time LIKE'[0-9][0-9]:[0-9][0-9]:[0-9][0-9]')
          BEGIN
               SET @HH=CAST(SUBSTRING(@Time, 1, 2) AS INT)
               SET @MM=CAST(SUBSTRING(@Time, 4, 2) AS INT)
               SET @SS=CAST(SUBSTRING(@Time, 7, 2) AS INT)
               IF((@HH BETWEEN 0 AND 23)AND (@MM BETWEEN 0 AND 59) AND(@SS BETWEEN 0 AND 59))
                    BEGIN
                         SET @ReturnValue=1
                    END
               ELSE
                    BEGIN
                         SET @ReturnValue=0
                    END
          END
     ELSE
          SET @ReturnValue=0
     RETURN @ReturnValue
END

Here we have added two functions ValidateDate and ValidateTime for validating Date and Time. Date accept data in (dd/mm/yyyy) format and Time accept data in (hh:mm:ss) format.

Step 4: Add Constraint to the Columns

ALTER TABLE Student
WITH NOCHECK -- Optional
ADD CONSTRAINT chkDate CHECK(dbo.ValidateDate(DateOfBirth)=1)

ALTER TABLE Student
WITH NOCHECK -- Optional
ADD CONSTRAINT chkTime CHECK(dbo.ValidateTime(TimeOfBirth)=1)

Here we have added two CHECK CONSTRAINT, ‘chkDate’ and ‘chkTime’ to the DateOfBirth and TimeOfBirth columns respectively for validating data inserted in these columns.

If you try to insert data in DateOfBirth and TimeOfBirth columns in a format other than specified, you will get an error stating “Conflicted with CHECK constraint”

Happy Programming!