How to use openxml in a custom function in SQL Server
I have an XML structure that I am parsing using OPENXML
in a stored procedure to retrieve the parameters used to make a request. This procedure was a basic procedure calling another stored procedure (procedure 2). Procedure 2 uses insert-exec to retrieve data from the underlying procedure. This works great as long as we only call procedure 2 or the base procedure.
My first problem is that I have another procedure (procedure 3) that should now get the result from procedure 2 (I need the business rules this procedure enforces), but cannot because of the message:
INSERT EXEC statement cannot be nested.
Then I tried to follow the basic procedure and make it a table function, but when I followed it, I get the message:
Only functions and some extended stored procedures can be executed within a function.
How do you get around one or both of these problems?
EDIT 1 I am including a code snippet to show the basic procedure (Procedure 1) and the procedure for fulfilling the business requirements resulting from this procedure (Procedure 2). If there is a 3rd procedure that needs results using business rules, we run into problems.
create procedure dbo.p_Proc
@Xml xml
as
begin
set nocount on;
declare @l_idoc int
, @InfoId int
, @InfoTypeId int
, @Id int
, @Name varchar(50)
, @StatusId int
, @RoleId int
, @XmlBase xml
, @l_path varchar(100);
declare @T_TABLE table(
InfoId int
, InfoTypeId int
);
declare @T_RESULT table
(
Field1 int
, Field2 varchar(50)
, Field3 int
);
EXEC sp_xml_preparedocument @l_idoc OUTPUT, @Xml;
set @l_path = '/xml/Info';
insert into @T_TABLE(InfoId, InfoTypeId)
select InfoId, InfoTypeId
from OPENXML (@l_idoc, @l_path, 1)
with (
InfoId int './@InfoId'
, InfoTypeId int './@InfoTypeId'
);
select @InfoId = InfoId
, @InfoTypeId = InfoTypeId
from @T_TABLE;
-- create the XML to call the base widgets
select @XmlBase =
(
select *
from
(
select t.Id, t.Name, t.StatusId, t.RoleId
from @T_TABLE w
inner join dbo.T_TABLE2 t
on t.InfoId = w.InfoId
and t.InfoTypeId = w.InfoTypeId
) b
for xml raw('Widget'), root('Xml')
);
-- retrieve widgets from base security
insert into @T_RESULT(Field1, Field2, Field3)
exec dbo.p_ProcBase @Xml = @XmlBase;
-- apply business logic here
select w.Field1, w.Field2, w.Field3
from @T_RESULT w;
end;
go
create procedure dbo.p_ProcBase
@Xml xml = null
as
begin
set nocount on;
declare @l_idoc int
, @Id int
, @Name varchar(50)
, @StatusId int
, @RoleId int
, @l_path varchar(100);
declare @T_Table table(
Id int
, Name varchar(50)
, StatusId int
, RoleId int
);
EXEC sp_xml_preparedocument @l_idoc OUTPUT, @Xml;
set @l_path = '/Xml/Widget';
insert into @T_Table(Id, Name, StatusId, RoleId)
select Id, Name, StatusId, RoleId
from OPENXML (@l_idoc, @l_path, 1)
with (
ProjectId int './@Id'
, WidgetTypeName varchar(50) './@Name'
, WorkflowStatusId int './@StatusId'
, UserRoleId bigint './@RoleId'
);
select @Id = w.Id
, @Name = w.Name
, @StatusId = w.StatusId
, @RoleId = w.RoleId
from @T_Table w;
-- retrieve enabled widgets for which the user has a role in the current workflow state
select t.Field1, t.Field2, t.Field3
from dbo.T_TABLE t
where t.StatusId = @StatusId
and t.RoleId = @RoleId;
end;
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To send a dataset (table) between procs, you must use the table type, store the proc2 result in a table type variable, and add only the read-only table type to proc3
First you have to create a table type to map the output to proc2:
CREATE TYPE T_RESULT AS TABLE
(
Field1 int
, Field2 varchar(50)
, Field3 int
);
In dbo.p_Proc
change @T_RESULT
to:
declare @T_RESULT T_RESULT
Then create proc3:
CREATE PROCEDURE dbo.proc3
@T_RESULT T_RESULT READONLY
AS
BEGIN
SET NOCOUNT ON
INSERT INTO T3(...)
SELECT ... FROM @T_RESULT
END
Don't forget to add READONLY after the table type parameter in proc.
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