Enter null values for datetime column of SQL Server

Source: Internet
Author: User

Http://www.c-sharpcorner.com/UploadFile/sd_patel/EnterNullValuesForDateTime11222005015742AM/EnterNullValuesForDateTime.aspx

 

Intrby Sushila Patel September 26,200 3

Inserting a null value to the datetime field in SQL Server is one of the most common issues giving various errors. even if one enters null values the value in the database is some default value as 1/1/1900 12:00:00 AM.

Oduction:

Inserting a null value to the datetime field in SQL Server is one of the most common issues giving various errors. even if one enters null values the value in the database is some default value as 1/1/1900 12:00:00 AM.

The output of entering the null datetime based on the Code wocould in most cases have errors:

  • String was not recognized as a valid datetime.
  • Value of Type 'System. dbnull' cannot be converted to 'string '.

Or no error but datatime entered in database wocould be as 1/1/1900 12:00:00 AM
So lets write the code to enter null values in the database.

The user interface is as follows:

To begin with code:

Namespaces used

System. Data. sqlclient/system. Data. oledb

  • System. Data. sqltypes
  • Code for system. Data. sqlclient
  • C #

    String sqlstmt;
    String constring;
    Sqlconnection Cn = NULL;
    Sqlcommand cmd = NULL;
    Sqldatetime sqldatenull;
    Try
    {
    Sqlstmt = "insert into EMP (firstname, lastname, date) values (@ firstname, @ lastname, @ date )";
    Constring = "Server = localhost; database = northwind; uid = sa; Pwd = ;";
    CN = new sqlconnection (constring );
    Cmd = new sqlcommand (sqlstmt, CN );
    Cmd. Parameters. Add (New sqlparameter ("@ firstname", sqldbtype. nvarchar, 11 ));
    Cmd. Parameters. Add (New sqlparameter ("@ lastname", sqldbtype. nvarchar, 40 ));
    Cmd. Parameters. Add (New sqlparameter ("@ date", sqldbtype. datetime ));
    Sqldatenull = sqldatetime. null;
    Cmd. Parameters ["@ firstname"]. value = txtfirstname. text;
    Cmd. Parameters ["@ lastname"]. value = txtlastname. text;
    If (txtdate. Text = "")
    {
    Cmd. Parameters ["@ date"]. value = sqldatenull;
    // Cmd. Parameters ["@ date"]. value = dbnull. value;
    }
    Else
    {
    Cmd. Parameters ["@ date"]. value = datetime. parse (txtdate. Text );
    }
    CN. open ();
    Cmd. executenonquery ();
    Label1.text = "record inserted succesfully ";
    }
    Catch (exception ex)
    {
    Label1.text = ex. message;
    }
    Finally
    {
    CN. Close ();
    }

    VB. NET

    Dim sqlstmt as string
    Dim constring as string
    Dim cn as sqlconnection
    Dim cmd as sqlcommand
    Dim sqldatenull as sqldatetime
    Try
    Sqlstmt = "insert into EMP (firstname, lastname, date) values (@ firstname, @ lastname, @ date )"
    Constring = "Server = localhost; database = northwind; uid = sa; Pwd = ;"
    CN = new sqlconnection (constring)
    Cmd = new sqlcommand (sqlstmt, CN)
    Cmd. Parameters. Add (New sqlparameter ("@ firstname", sqldbtype. nvarchar, 11 ))
    Cmd. Parameters. Add (New sqlparameter ("@ lastname", sqldbtype. nvarchar, 40) cmd. Parameters. Add (New sqlparameter ("@ date", sqldbtype. datetime ))
    Sqldatenull = sqldatetime. null
    Cmd. parameters ("@ firstname"). value = txtfirstname. Text
    Cmd. parameters ("@ lastname"). value = txtlastname. Text
    If (txtdate. Text = "") then
    Cmd. parameters ("@ date"). value = sqldatenull
    'Cmd. parameters ("@ date"). value = dbnull. Value
    Else
    Cmd. parameters ("@ date"). value = datetime. parse (txtdate. Text)
    End if
    CN. open ()
    Cmd. executenonquery ()
    Label1.text = "record inserted succesfully"
    Catch ex as exception
    Label1.text = ex. Message
    Finally
    CN. Close ()
    End try

    Code for system. Data. sqlclient.

    C #

    String sqlstmt;
    String constring;
    Oledbconnection Cn = NULL;
    Oledbcommand cmd = NULL;
    Try
    {
    Sqlstmt = "insert into EMP (firstname, lastname, date) values (?,?,?) ";
    Constring = "provider = sqloledb.1; user id = sa; Pwd =; database = northwind; Data Source = localhost ";
    CN = new oledbconnection (constring );
    Cmd = new oledbcommand (sqlstmt, CN );
    Cmd. Parameters. Add (New oledbparameter ("@ firstname", oledbtype. varchar, 40 ));
    Cmd. Parameters. Add (New oledbparameter ("@ lastname", oledbtype. varchar, 40 ));
    Cmd. Parameters. Add (New oledbparameter ("@ date", oledbtype. Date ));
    Cmd. Parameters ["@ firstname"]. value = txtfirstname. text;
    Cmd. Parameters ["@ lastname"]. value = txtlastname. text;
    If (txtdate. Text = ""))
    {
    Cmd. Parameters ["@ date"]. value = dbnull. value;
    }
    Else
    {
    Cmd. Parameters ["@ date"]. value = datetime. parse (txtdate. Text );
    }
    CN. open ();
    Cmd. executenonquery ();
    Label1.text = "record inserted succesfully ";
    }
    Catch (exception ex)
    {
    Label1.text = ex. message;
    }
    Finally
    {
    CN. Close ();
    }

    VB. NET

    Dim sqlstmt as string
    Dim constring as string
    Dim cn as oledbconnection
    Dim cmd as oledbcommand
    Try
    Sqlstmt = "insert into EMP (firstname, lastname, date) values (?,?,?) "
    Constring = "provider = sqloledb.1; user id = sa; Pwd =; database = northwind; Data Source = localhost"
    CN = new oledbconnection (constring)
    Cmd = new oledbcommand (sqlstmt, CN)
    Cmd. parameters. add (New oledbparameter ("@ firstname", oledbtype. varchar, 40) cmd. parameters. add (New oledbparameter ("@ lastname", oledbtype. varchar, 40) cmd. parameters. add (New oledbparameter ("@ date", oledbtype. date) cmd. parameters ("@ firstname "). value = txtfirstname. text
    Cmd. parameters ("@ lastname"). value = txtlastname. Text
    If (txtdate. Text = "") then
    Cmd. parameters ("@ date"). value = dbnull. Value
    Else
    Cmd. parameters ("@ date"). value = datetime. parse (txtdate. Text)
    End if
    CN. open ()
    Cmd. executenonquery ()
    Label1.text = "record inserted succesfully"
    Catch ex as exception
    Label1.text = ex. Message
    Finally
    CN. Close ()
    End try

    The data entered in database:

     

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