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ObjectDataSource - problem inserting empty field into stored proce

P: n/a
I'm using an ObjectDataSource with a stored procedure and am getting the
following error when trying to update (ExecuteNonQuery):

System.Data.SqlClient.SqlException: Procedure or Function 'UpdateRegistrant'
expects parameter '@EMail', which was not supplied.

The field value was null in the database and not changed in the FormView so
is null going back into the stored procedure. I'm stumped and would greatly
appreciate any suggestions.

TypeName code from RegistrantDB:
public void UpdateRegistrant(
RegistrantDetails reg
) {
SqlConnection con = new SqlConnection( connectionString );
SqlCommand cmd = new SqlCommand( "UpdateRegistrant", con );
cmd.CommandType = CommandType.StoredProcedure;
...
cmd.Parameters.Add( new SqlParameter( "@EMail", SqlDbType.NVarChar, 25 ) );
cmd.Parameters["@EMail"].Value = reg.EMail;
...
con.Open();
cmd.ExecuteNonQuery();
con.Close();

code from my DataObjectTypeName RegistrantDetails:
protected string eMail = String.Empty;
public string EMail
{
get {return eMail;}
set {eMail = value;}
}

My stored procedure UpdateRegistrant:
CREATE PROCEDURE [dbo].UpdateRegistrant
@RegistrantId int,
@FirstName nvarchar(25),
@MI nvarchar(3),
@LastName nvarchar(25),
@EMail nvarchar(25),
...
AS
UPDATE [dbo].[Registrants] SET
[FirstName] = @FirstName,
[MI] = @MI,
[LastName] = @LastName,
[email] = @EMail,
...
WHERE
[RegistrantId] = @RegistrantId

Apr 7 '06 #1
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7 Replies


P: n/a
Dabbler,

When you add a parameter to your sqlcommand with the value null or even an
empty string, the stored procedure will think the parameter is not supplied.

There are two ways to solve your problem:
1: Alter your stored procedure to allow the Email parameter (and maybe
others) to be null:

CREATE PROCEDURE [dbo].UpdateRegistrant
@RegistrantId int,
@FirstName nvarchar(25),
@MI nvarchar(3),
@LastName nvarchar(25),
@EMail nvarchar(25) = null,
...
AS

2: When passing the parameter to the sqlcommand ensure that the value is not
null or an empty string:
if (reg.EMail == null || reg.EMail.Length ==0)
reg.EMail = "dummy value";
cmd.Parameters["@EMail"].Value = reg.EMail;

Good luck.

Regards, Dustin.

"Dabbler" wrote:
I'm using an ObjectDataSource with a stored procedure and am getting the
following error when trying to update (ExecuteNonQuery):

System.Data.SqlClient.SqlException: Procedure or Function 'UpdateRegistrant'
expects parameter '@EMail', which was not supplied.

The field value was null in the database and not changed in the FormView so
is null going back into the stored procedure. I'm stumped and would greatly
appreciate any suggestions.

TypeName code from RegistrantDB:
public void UpdateRegistrant(
RegistrantDetails reg
) {
SqlConnection con = new SqlConnection( connectionString );
SqlCommand cmd = new SqlCommand( "UpdateRegistrant", con );
cmd.CommandType = CommandType.StoredProcedure;
...
cmd.Parameters.Add( new SqlParameter( "@EMail", SqlDbType.NVarChar, 25 ) );
cmd.Parameters["@EMail"].Value = reg.EMail;
...
con.Open();
cmd.ExecuteNonQuery();
con.Close();

code from my DataObjectTypeName RegistrantDetails:
protected string eMail = String.Empty;
public string EMail
{
get {return eMail;}
set {eMail = value;}
}

My stored procedure UpdateRegistrant:
CREATE PROCEDURE [dbo].UpdateRegistrant
@RegistrantId int,
@FirstName nvarchar(25),
@MI nvarchar(3),
@LastName nvarchar(25),
@EMail nvarchar(25),
...
AS
UPDATE [dbo].[Registrants] SET
[FirstName] = @FirstName,
[MI] = @MI,
[LastName] = @LastName,
[email] = @EMail,
...
WHERE
[RegistrantId] = @RegistrantId

Apr 7 '06 #2

P: n/a
Hi Dustin

Thanks for that clarification. I'm wondering what the best practices is for
this, as I've been pouring over other developers ObjectDataSource examples
using business classes and stored procedures and nowhere do I see a hint of
coding to deal with null values.

Do people typically initialize db table columns to "" instead of leaving
them null?

Thanks again for this info, I have 50+ columns in this table and form so I
think the easiest thing to do is renegerate the stored procedure (using
Codesmith) with null as default value. I'm really loosing my interest in
ObjectDataSource, given the gray hair it's given me ;)

"Dustin van de Sande" wrote:
Dabbler,

When you add a parameter to your sqlcommand with the value null or even an
empty string, the stored procedure will think the parameter is not supplied.

There are two ways to solve your problem:
1: Alter your stored procedure to allow the Email parameter (and maybe
others) to be null:

CREATE PROCEDURE [dbo].UpdateRegistrant
@RegistrantId int,
@FirstName nvarchar(25),
@MI nvarchar(3),
@LastName nvarchar(25),
@EMail nvarchar(25) = null,
...
AS

2: When passing the parameter to the sqlcommand ensure that the value is not
null or an empty string:
if (reg.EMail == null || reg.EMail.Length ==0)
reg.EMail = "dummy value";
cmd.Parameters["@EMail"].Value = reg.EMail;

Good luck.

Regards, Dustin.

"Dabbler" wrote:
I'm using an ObjectDataSource with a stored procedure and am getting the
following error when trying to update (ExecuteNonQuery):

System.Data.SqlClient.SqlException: Procedure or Function 'UpdateRegistrant'
expects parameter '@EMail', which was not supplied.

The field value was null in the database and not changed in the FormView so
is null going back into the stored procedure. I'm stumped and would greatly
appreciate any suggestions.

TypeName code from RegistrantDB:
public void UpdateRegistrant(
RegistrantDetails reg
) {
SqlConnection con = new SqlConnection( connectionString );
SqlCommand cmd = new SqlCommand( "UpdateRegistrant", con );
cmd.CommandType = CommandType.StoredProcedure;
...
cmd.Parameters.Add( new SqlParameter( "@EMail", SqlDbType.NVarChar, 25 ) );
cmd.Parameters["@EMail"].Value = reg.EMail;
...
con.Open();
cmd.ExecuteNonQuery();
con.Close();

code from my DataObjectTypeName RegistrantDetails:
protected string eMail = String.Empty;
public string EMail
{
get {return eMail;}
set {eMail = value;}
}

My stored procedure UpdateRegistrant:
CREATE PROCEDURE [dbo].UpdateRegistrant
@RegistrantId int,
@FirstName nvarchar(25),
@MI nvarchar(3),
@LastName nvarchar(25),
@EMail nvarchar(25),
...
AS
UPDATE [dbo].[Registrants] SET
[FirstName] = @FirstName,
[MI] = @MI,
[LastName] = @LastName,
[email] = @EMail,
...
WHERE
[RegistrantId] = @RegistrantId

Apr 7 '06 #3

P: n/a
Hi Dabbler,

I normally use the objectdatasource so I can use a typed dataset without
stored procedures.
The stored procedures I normally use on heavy calculation jobs or multiple
db updates, not single records.
However I don't believe it's a problem to have your nullable fields as a
nullable parameter in a stored procedure.

Good luck.

"Dabbler" wrote:
Hi Dustin

Thanks for that clarification. I'm wondering what the best practices is for
this, as I've been pouring over other developers ObjectDataSource examples
using business classes and stored procedures and nowhere do I see a hint of
coding to deal with null values.

Do people typically initialize db table columns to "" instead of leaving
them null?

Thanks again for this info, I have 50+ columns in this table and form so I
think the easiest thing to do is renegerate the stored procedure (using
Codesmith) with null as default value. I'm really loosing my interest in
ObjectDataSource, given the gray hair it's given me ;)

"Dustin van de Sande" wrote:
Dabbler,

When you add a parameter to your sqlcommand with the value null or even an
empty string, the stored procedure will think the parameter is not supplied.

There are two ways to solve your problem:
1: Alter your stored procedure to allow the Email parameter (and maybe
others) to be null:

CREATE PROCEDURE [dbo].UpdateRegistrant
@RegistrantId int,
@FirstName nvarchar(25),
@MI nvarchar(3),
@LastName nvarchar(25),
@EMail nvarchar(25) = null,
...
AS

2: When passing the parameter to the sqlcommand ensure that the value is not
null or an empty string:
if (reg.EMail == null || reg.EMail.Length ==0)
reg.EMail = "dummy value";
cmd.Parameters["@EMail"].Value = reg.EMail;

Good luck.

Regards, Dustin.

"Dabbler" wrote:
I'm using an ObjectDataSource with a stored procedure and am getting the
following error when trying to update (ExecuteNonQuery):

System.Data.SqlClient.SqlException: Procedure or Function 'UpdateRegistrant'
expects parameter '@EMail', which was not supplied.

The field value was null in the database and not changed in the FormView so
is null going back into the stored procedure. I'm stumped and would greatly
appreciate any suggestions.

TypeName code from RegistrantDB:
public void UpdateRegistrant(
RegistrantDetails reg
) {
SqlConnection con = new SqlConnection( connectionString );
SqlCommand cmd = new SqlCommand( "UpdateRegistrant", con );
cmd.CommandType = CommandType.StoredProcedure;
...
cmd.Parameters.Add( new SqlParameter( "@EMail", SqlDbType.NVarChar, 25 ) );
cmd.Parameters["@EMail"].Value = reg.EMail;
...
con.Open();
cmd.ExecuteNonQuery();
con.Close();

code from my DataObjectTypeName RegistrantDetails:
protected string eMail = String.Empty;
public string EMail
{
get {return eMail;}
set {eMail = value;}
}

My stored procedure UpdateRegistrant:
CREATE PROCEDURE [dbo].UpdateRegistrant
@RegistrantId int,
@FirstName nvarchar(25),
@MI nvarchar(3),
@LastName nvarchar(25),
@EMail nvarchar(25),
...
AS
UPDATE [dbo].[Registrants] SET
[FirstName] = @FirstName,
[MI] = @MI,
[LastName] = @LastName,
[email] = @EMail,
...
WHERE
[RegistrantId] = @RegistrantId

Apr 7 '06 #4

P: n/a
Dustin

What happens if I have a datetime field which is not on my form, but is in
my object class and is pushed into the stored procedure. If I set the stored
procedure to JoinDate = null will it simply ignore this column in the update
or will it replace the value with null?

Thanks again, I think the fog is lifting... ;)

"Dustin van de Sande" wrote:
Hi Dabbler,

I normally use the objectdatasource so I can use a typed dataset without
stored procedures.
The stored procedures I normally use on heavy calculation jobs or multiple
db updates, not single records.
However I don't believe it's a problem to have your nullable fields as a
nullable parameter in a stored procedure.

Good luck.

"Dabbler" wrote:
Hi Dustin

Thanks for that clarification. I'm wondering what the best practices is for
this, as I've been pouring over other developers ObjectDataSource examples
using business classes and stored procedures and nowhere do I see a hint of
coding to deal with null values.

Do people typically initialize db table columns to "" instead of leaving
them null?

Thanks again for this info, I have 50+ columns in this table and form so I
think the easiest thing to do is renegerate the stored procedure (using
Codesmith) with null as default value. I'm really loosing my interest in
ObjectDataSource, given the gray hair it's given me ;)

"Dustin van de Sande" wrote:
Dabbler,

When you add a parameter to your sqlcommand with the value null or even an
empty string, the stored procedure will think the parameter is not supplied.

There are two ways to solve your problem:
1: Alter your stored procedure to allow the Email parameter (and maybe
others) to be null:

CREATE PROCEDURE [dbo].UpdateRegistrant
@RegistrantId int,
@FirstName nvarchar(25),
@MI nvarchar(3),
@LastName nvarchar(25),
@EMail nvarchar(25) = null,
...
AS

2: When passing the parameter to the sqlcommand ensure that the value is not
null or an empty string:
if (reg.EMail == null || reg.EMail.Length ==0)
reg.EMail = "dummy value";
cmd.Parameters["@EMail"].Value = reg.EMail;

Good luck.

Regards, Dustin.

"Dabbler" wrote:

> I'm using an ObjectDataSource with a stored procedure and am getting the
> following error when trying to update (ExecuteNonQuery):
>
> System.Data.SqlClient.SqlException: Procedure or Function 'UpdateRegistrant'
> expects parameter '@EMail', which was not supplied.
>
> The field value was null in the database and not changed in the FormView so
> is null going back into the stored procedure. I'm stumped and would greatly
> appreciate any suggestions.
>
> TypeName code from RegistrantDB:
> public void UpdateRegistrant(
> RegistrantDetails reg
> ) {
> SqlConnection con = new SqlConnection( connectionString );
> SqlCommand cmd = new SqlCommand( "UpdateRegistrant", con );
> cmd.CommandType = CommandType.StoredProcedure;
> ...
> cmd.Parameters.Add( new SqlParameter( "@EMail", SqlDbType.NVarChar, 25 ) );
> cmd.Parameters["@EMail"].Value = reg.EMail;
> ...
> con.Open();
> cmd.ExecuteNonQuery();
> con.Close();
>
> code from my DataObjectTypeName RegistrantDetails:
> protected string eMail = String.Empty;
> public string EMail
> {
> get {return eMail;}
> set {eMail = value;}
> }
>
> My stored procedure UpdateRegistrant:
> CREATE PROCEDURE [dbo].UpdateRegistrant
> @RegistrantId int,
> @FirstName nvarchar(25),
> @MI nvarchar(3),
> @LastName nvarchar(25),
> @EMail nvarchar(25),
> ...
> AS
> UPDATE [dbo].[Registrants] SET
> [FirstName] = @FirstName,
> [MI] = @MI,
> [LastName] = @LastName,
> [email] = @EMail,
> ...
> WHERE
> [RegistrantId] = @RegistrantId
>

Apr 7 '06 #5

P: n/a
Dabbler,

If you have the date in your update statement it will update the value with
null. You can create a script to bypass this, but I don't think you should.
If @Joindate is null
begin
update ....
end
else
begin
update
end

Another way could be to generate a sql statement in a varchar to update the
fields supplied:
declare @sqlstring varchar(2000)
set @sqlstring = 'Update tbl_table set '
if @JoinDate is null
begin
set @sqlstring = @sqlstring + 'joindate='+ @JoinDate --Probably you will
have to cast this
end
--Other params
exec @sqlstring

Beware of the permissions however. When you use an sql string in your sp,
the user will need rights to the table aswell.

Another method (which I prefer) is of course to use a typed dataset in your
business layer.

"Dabbler" wrote:
Dustin

What happens if I have a datetime field which is not on my form, but is in
my object class and is pushed into the stored procedure. If I set the stored
procedure to JoinDate = null will it simply ignore this column in the update
or will it replace the value with null?

Thanks again, I think the fog is lifting... ;)

"Dustin van de Sande" wrote:
Hi Dabbler,

I normally use the objectdatasource so I can use a typed dataset without
stored procedures.
The stored procedures I normally use on heavy calculation jobs or multiple
db updates, not single records.
However I don't believe it's a problem to have your nullable fields as a
nullable parameter in a stored procedure.

Good luck.

"Dabbler" wrote:
Hi Dustin

Thanks for that clarification. I'm wondering what the best practices is for
this, as I've been pouring over other developers ObjectDataSource examples
using business classes and stored procedures and nowhere do I see a hint of
coding to deal with null values.

Do people typically initialize db table columns to "" instead of leaving
them null?

Thanks again for this info, I have 50+ columns in this table and form so I
think the easiest thing to do is renegerate the stored procedure (using
Codesmith) with null as default value. I'm really loosing my interest in
ObjectDataSource, given the gray hair it's given me ;)

"Dustin van de Sande" wrote:

> Dabbler,
>
> When you add a parameter to your sqlcommand with the value null or even an
> empty string, the stored procedure will think the parameter is not supplied.
>
> There are two ways to solve your problem:
> 1: Alter your stored procedure to allow the Email parameter (and maybe
> others) to be null:
>
> CREATE PROCEDURE [dbo].UpdateRegistrant
> @RegistrantId int,
> @FirstName nvarchar(25),
> @MI nvarchar(3),
> @LastName nvarchar(25),
> @EMail nvarchar(25) = null,
> ...
> AS
>
> 2: When passing the parameter to the sqlcommand ensure that the value is not
> null or an empty string:
> if (reg.EMail == null || reg.EMail.Length ==0)
> reg.EMail = "dummy value";
> cmd.Parameters["@EMail"].Value = reg.EMail;
>
> Good luck.
>
> Regards, Dustin.
>
> "Dabbler" wrote:
>
> > I'm using an ObjectDataSource with a stored procedure and am getting the
> > following error when trying to update (ExecuteNonQuery):
> >
> > System.Data.SqlClient.SqlException: Procedure or Function 'UpdateRegistrant'
> > expects parameter '@EMail', which was not supplied.
> >
> > The field value was null in the database and not changed in the FormView so
> > is null going back into the stored procedure. I'm stumped and would greatly
> > appreciate any suggestions.
> >
> > TypeName code from RegistrantDB:
> > public void UpdateRegistrant(
> > RegistrantDetails reg
> > ) {
> > SqlConnection con = new SqlConnection( connectionString );
> > SqlCommand cmd = new SqlCommand( "UpdateRegistrant", con );
> > cmd.CommandType = CommandType.StoredProcedure;
> > ...
> > cmd.Parameters.Add( new SqlParameter( "@EMail", SqlDbType.NVarChar, 25 ) );
> > cmd.Parameters["@EMail"].Value = reg.EMail;
> > ...
> > con.Open();
> > cmd.ExecuteNonQuery();
> > con.Close();
> >
> > code from my DataObjectTypeName RegistrantDetails:
> > protected string eMail = String.Empty;
> > public string EMail
> > {
> > get {return eMail;}
> > set {eMail = value;}
> > }
> >
> > My stored procedure UpdateRegistrant:
> > CREATE PROCEDURE [dbo].UpdateRegistrant
> > @RegistrantId int,
> > @FirstName nvarchar(25),
> > @MI nvarchar(3),
> > @LastName nvarchar(25),
> > @EMail nvarchar(25),
> > ...
> > AS
> > UPDATE [dbo].[Registrants] SET
> > [FirstName] = @FirstName,
> > [MI] = @MI,
> > [LastName] = @LastName,
> > [email] = @EMail,
> > ...
> > WHERE
> > [RegistrantId] = @RegistrantId
> >

Apr 7 '06 #6

P: n/a
Wow, I wasn't aware of this drawback using stored procedures. I thought I
could use an object class (commuter) and a db class to retrieve/store the
form fields. Given the number of fields involved these options would get
pretty ugly.

In your preferred DataSet scenario how do you get the data from the dataset
columns in and out of the form fields? Do you set them one by one in the code
behind file or do you have some other way of binding the field values?

Thanks for your time in getting me past these hurdles.

"Dustin van de Sande" wrote:
Dabbler,

If you have the date in your update statement it will update the value with
null. You can create a script to bypass this, but I don't think you should.
If @Joindate is null
begin
update ....
end
else
begin
update
end

Another way could be to generate a sql statement in a varchar to update the
fields supplied:
declare @sqlstring varchar(2000)
set @sqlstring = 'Update tbl_table set '
if @JoinDate is null
begin
set @sqlstring = @sqlstring + 'joindate='+ @JoinDate --Probably you will
have to cast this
end
--Other params
exec @sqlstring

Beware of the permissions however. When you use an sql string in your sp,
the user will need rights to the table aswell.

Another method (which I prefer) is of course to use a typed dataset in your
business layer.

"Dabbler" wrote:
Dustin

What happens if I have a datetime field which is not on my form, but is in
my object class and is pushed into the stored procedure. If I set the stored
procedure to JoinDate = null will it simply ignore this column in the update
or will it replace the value with null?

Thanks again, I think the fog is lifting... ;)

"Dustin van de Sande" wrote:
Hi Dabbler,

I normally use the objectdatasource so I can use a typed dataset without
stored procedures.
The stored procedures I normally use on heavy calculation jobs or multiple
db updates, not single records.
However I don't believe it's a problem to have your nullable fields as a
nullable parameter in a stored procedure.

Good luck.

"Dabbler" wrote:

> Hi Dustin
>
> Thanks for that clarification. I'm wondering what the best practices is for
> this, as I've been pouring over other developers ObjectDataSource examples
> using business classes and stored procedures and nowhere do I see a hint of
> coding to deal with null values.
>
> Do people typically initialize db table columns to "" instead of leaving
> them null?
>
> Thanks again for this info, I have 50+ columns in this table and form so I
> think the easiest thing to do is renegerate the stored procedure (using
> Codesmith) with null as default value. I'm really loosing my interest in
> ObjectDataSource, given the gray hair it's given me ;)
>
> "Dustin van de Sande" wrote:
>
> > Dabbler,
> >
> > When you add a parameter to your sqlcommand with the value null or even an
> > empty string, the stored procedure will think the parameter is not supplied.
> >
> > There are two ways to solve your problem:
> > 1: Alter your stored procedure to allow the Email parameter (and maybe
> > others) to be null:
> >
> > CREATE PROCEDURE [dbo].UpdateRegistrant
> > @RegistrantId int,
> > @FirstName nvarchar(25),
> > @MI nvarchar(3),
> > @LastName nvarchar(25),
> > @EMail nvarchar(25) = null,
> > ...
> > AS
> >
> > 2: When passing the parameter to the sqlcommand ensure that the value is not
> > null or an empty string:
> > if (reg.EMail == null || reg.EMail.Length ==0)
> > reg.EMail = "dummy value";
> > cmd.Parameters["@EMail"].Value = reg.EMail;
> >
> > Good luck.
> >
> > Regards, Dustin.
> >
> > "Dabbler" wrote:
> >
> > > I'm using an ObjectDataSource with a stored procedure and am getting the
> > > following error when trying to update (ExecuteNonQuery):
> > >
> > > System.Data.SqlClient.SqlException: Procedure or Function 'UpdateRegistrant'
> > > expects parameter '@EMail', which was not supplied.
> > >
> > > The field value was null in the database and not changed in the FormView so
> > > is null going back into the stored procedure. I'm stumped and would greatly
> > > appreciate any suggestions.
> > >
> > > TypeName code from RegistrantDB:
> > > public void UpdateRegistrant(
> > > RegistrantDetails reg
> > > ) {
> > > SqlConnection con = new SqlConnection( connectionString );
> > > SqlCommand cmd = new SqlCommand( "UpdateRegistrant", con );
> > > cmd.CommandType = CommandType.StoredProcedure;
> > > ...
> > > cmd.Parameters.Add( new SqlParameter( "@EMail", SqlDbType.NVarChar, 25 ) );
> > > cmd.Parameters["@EMail"].Value = reg.EMail;
> > > ...
> > > con.Open();
> > > cmd.ExecuteNonQuery();
> > > con.Close();
> > >
> > > code from my DataObjectTypeName RegistrantDetails:
> > > protected string eMail = String.Empty;
> > > public string EMail
> > > {
> > > get {return eMail;}
> > > set {eMail = value;}
> > > }
> > >
> > > My stored procedure UpdateRegistrant:
> > > CREATE PROCEDURE [dbo].UpdateRegistrant
> > > @RegistrantId int,
> > > @FirstName nvarchar(25),
> > > @MI nvarchar(3),
> > > @LastName nvarchar(25),
> > > @EMail nvarchar(25),
> > > ...
> > > AS
> > > UPDATE [dbo].[Registrants] SET
> > > [FirstName] = @FirstName,
> > > [MI] = @MI,
> > > [LastName] = @LastName,
> > > [email] = @EMail,
> > > ...
> > > WHERE
> > > [RegistrantId] = @RegistrantId
> > >

Apr 7 '06 #7

P: n/a
When you have to update a lot of fields in a table, a stored procedure isn't
always the best solution indeed.

In my solutions I add a dataset to my businesslayer.
In my webapplication I create an objectdatasource to the dataset in the
businesslayer and bind a formview control to it. You can specify which
get/set/delete command the formview control should use.
All the fields are automatically bound to the formview.
You can create your own template for the edit and readonly mode (and if you
prefer even one for the insert mode. This one is automatically added, but
when deleted it uses the edit mode!)

Your welcome.

"Dabbler" wrote:
Wow, I wasn't aware of this drawback using stored procedures. I thought I
could use an object class (commuter) and a db class to retrieve/store the
form fields. Given the number of fields involved these options would get
pretty ugly.

In your preferred DataSet scenario how do you get the data from the dataset
columns in and out of the form fields? Do you set them one by one in the code
behind file or do you have some other way of binding the field values?

Thanks for your time in getting me past these hurdles.

"Dustin van de Sande" wrote:
Dabbler,

If you have the date in your update statement it will update the value with
null. You can create a script to bypass this, but I don't think you should.
If @Joindate is null
begin
update ....
end
else
begin
update
end

Another way could be to generate a sql statement in a varchar to update the
fields supplied:
declare @sqlstring varchar(2000)
set @sqlstring = 'Update tbl_table set '
if @JoinDate is null
begin
set @sqlstring = @sqlstring + 'joindate='+ @JoinDate --Probably you will
have to cast this
end
--Other params
exec @sqlstring

Beware of the permissions however. When you use an sql string in your sp,
the user will need rights to the table aswell.

Another method (which I prefer) is of course to use a typed dataset in your
business layer.

"Dabbler" wrote:
Dustin

What happens if I have a datetime field which is not on my form, but is in
my object class and is pushed into the stored procedure. If I set the stored
procedure to JoinDate = null will it simply ignore this column in the update
or will it replace the value with null?

Thanks again, I think the fog is lifting... ;)

"Dustin van de Sande" wrote:

> Hi Dabbler,
>
> I normally use the objectdatasource so I can use a typed dataset without
> stored procedures.
> The stored procedures I normally use on heavy calculation jobs or multiple
> db updates, not single records.
> However I don't believe it's a problem to have your nullable fields as a
> nullable parameter in a stored procedure.
>
> Good luck.
>
> "Dabbler" wrote:
>
> > Hi Dustin
> >
> > Thanks for that clarification. I'm wondering what the best practices is for
> > this, as I've been pouring over other developers ObjectDataSource examples
> > using business classes and stored procedures and nowhere do I see a hint of
> > coding to deal with null values.
> >
> > Do people typically initialize db table columns to "" instead of leaving
> > them null?
> >
> > Thanks again for this info, I have 50+ columns in this table and form so I
> > think the easiest thing to do is renegerate the stored procedure (using
> > Codesmith) with null as default value. I'm really loosing my interest in
> > ObjectDataSource, given the gray hair it's given me ;)
> >
> > "Dustin van de Sande" wrote:
> >
> > > Dabbler,
> > >
> > > When you add a parameter to your sqlcommand with the value null or even an
> > > empty string, the stored procedure will think the parameter is not supplied.
> > >
> > > There are two ways to solve your problem:
> > > 1: Alter your stored procedure to allow the Email parameter (and maybe
> > > others) to be null:
> > >
> > > CREATE PROCEDURE [dbo].UpdateRegistrant
> > > @RegistrantId int,
> > > @FirstName nvarchar(25),
> > > @MI nvarchar(3),
> > > @LastName nvarchar(25),
> > > @EMail nvarchar(25) = null,
> > > ...
> > > AS
> > >
> > > 2: When passing the parameter to the sqlcommand ensure that the value is not
> > > null or an empty string:
> > > if (reg.EMail == null || reg.EMail.Length ==0)
> > > reg.EMail = "dummy value";
> > > cmd.Parameters["@EMail"].Value = reg.EMail;
> > >
> > > Good luck.
> > >
> > > Regards, Dustin.
> > >
> > > "Dabbler" wrote:
> > >
> > > > I'm using an ObjectDataSource with a stored procedure and am getting the
> > > > following error when trying to update (ExecuteNonQuery):
> > > >
> > > > System.Data.SqlClient.SqlException: Procedure or Function 'UpdateRegistrant'
> > > > expects parameter '@EMail', which was not supplied.
> > > >
> > > > The field value was null in the database and not changed in the FormView so
> > > > is null going back into the stored procedure. I'm stumped and would greatly
> > > > appreciate any suggestions.
> > > >
> > > > TypeName code from RegistrantDB:
> > > > public void UpdateRegistrant(
> > > > RegistrantDetails reg
> > > > ) {
> > > > SqlConnection con = new SqlConnection( connectionString );
> > > > SqlCommand cmd = new SqlCommand( "UpdateRegistrant", con );
> > > > cmd.CommandType = CommandType.StoredProcedure;
> > > > ...
> > > > cmd.Parameters.Add( new SqlParameter( "@EMail", SqlDbType.NVarChar, 25 ) );
> > > > cmd.Parameters["@EMail"].Value = reg.EMail;
> > > > ...
> > > > con.Open();
> > > > cmd.ExecuteNonQuery();
> > > > con.Close();
> > > >
> > > > code from my DataObjectTypeName RegistrantDetails:
> > > > protected string eMail = String.Empty;
> > > > public string EMail
> > > > {
> > > > get {return eMail;}
> > > > set {eMail = value;}
> > > > }
> > > >
> > > > My stored procedure UpdateRegistrant:
> > > > CREATE PROCEDURE [dbo].UpdateRegistrant
> > > > @RegistrantId int,
> > > > @FirstName nvarchar(25),
> > > > @MI nvarchar(3),
> > > > @LastName nvarchar(25),
> > > > @EMail nvarchar(25),
> > > > ...
> > > > AS
> > > > UPDATE [dbo].[Registrants] SET
> > > > [FirstName] = @FirstName,
> > > > [MI] = @MI,
> > > > [LastName] = @LastName,
> > > > [email] = @EMail,
> > > > ...
> > > > WHERE
> > > > [RegistrantId] = @RegistrantId
> > > >

Apr 10 '06 #8

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