Where should I find [sp_xml_preparedocument]? - sql-server

I recently used [sp_xml_preparedocument] to parse an XML file to analyze the parameter data.
What is interesting to me is that when I drill into my SQLServer 2k8r2 instance I cannot seem to actually find a procedure named [sp_xml_preparedocument].
I've been looking in System Databases/Mater and the Db I created for the analysis and it does not appear.
However [EXEC sp_xml_preparedocument #hdoc OUTPUT, #x] executes just fine.
I'd like to deepen my understanding of what is occurring and review the actual procedure.
Where should this stored procedure actually appear?

sp_xml_preparedocument is a system extended stored procedure. From SSMS Object Explorer, you'll find it under Databases-->System Databases-->Programmability-->System Extended Stored Procedures.
Since it's an unmanaged extended proc written in C++, not T-SQL, so you won't be able to review the source code. It used to just wrap the msxml COM API but I'm not sure if that's still the case nowadays since it's internal SQL Server code.

Related

Dynamic update or script equivalent in SQL Server in-memory OLTP (Hekaton)

I want to write equivalent stored procedure (contain execute string) in natively compiled stored procedure, but I can't find a way to implement that.
Does anyone have an idea?
There are limited set of operators that can be used in natively compiled stored procedures.
You are allowed to use control-of-flow language statements like IF and ELSE, so this is the closest thing you can get to dynamic execution.

where is SP_EXECUTESQL defined?

The 'SP_' prefix by convention suggests a system stored procedure. But nowhere in my SQL Server instance could I find the sp_executesql stored procedure.
I know it is there because it is used by one of my workplace's legacy code. But where is it? Where can I find it using MS SQL Server Management Studio?
Where can I find it using MS SQL Server Management Studio?
It is an extended stored procedure and you can't do anything useful with it having found it though (apart from managing permissions).
master --> Programmability --> Extended Stored Procedures --> System Extended Stored Procedures
It is present there , if you execute this query
`sp_helptext sp_executesql
you will get (Server Internal) because "sp_helptext" is a extended stored procedures so you cannot see it. They are processed in a dll rather than TSQL..
Refer this link
https://technet.microsoft.com/en-us/library/ms175200%28v=sql.105%29.aspx

CLR Stored Procedure v regular SQL Stored Procedure

I have been writing a CLR stored procedure that moves data from one database to another. I went with the CLR stored procedure because I like the .NET framework's ability to connect to remote servers better than I like linked servers, or openrowset, but I now find that my class is mostly embedded SQL strings. I was considering just using the CLR stored procedures to retrieve the data onto the local SQL Server, and then using a regular SQL stored procedure for the actual inserts and updates.
I'm not worried about pre-compilation of the procedure or performance, and I do like that the CLR procedure allows me to see all of the logic in one place, read from top to bottom.
Are there any reasons I should consider moving to a TSQL solution instead of CLR?
Thanks.
There are multiple reasons why you would stick to a regular stored procedure. I'll try to give you an overview of the ones that I know of:
Performance.
Memory issues. SQL Server only operates with its own max memory settings. CLR's go out of this bound. This could comprimise other applications (and the OS) running on this server.
Updatebility. You can update a Stored procedure with a simple script. CLR's are more complicated to update
Security. CLR's often require more security settings than regular t-sql.
As a general rule you only want to use CLR for:
interaction with the OS, such as reading from a file or dropping a message in MSMQ
performing complex calculations, especially when you already have the code written in a .NET language to do the calculation.

How do I automatically validate stored procedures against the database schema

A few years ago I came across a T-SQL technique to validate a stored procedure in SQL Server, but I cannot find it again
Can probably script the stored procedure calls out with SET NOEXEC ON, so it doesn't actually run anything... This would allow you to catch a lot of basic errors (invalid objects, missing fields, etc.)
Is that along the lines of what you were talking about?
If so, there's a CLR mentioned in SQL Mag that seems to do what you're looking for.

redeploying a .NET assembly that contains CLR stored procedures

I have written a CLR stored procedure that is in an assembly.
I have a build system that can auto-build and deploy .net application from our source control repository.
I want the two things to work together so I can redeploy the assembly that hosts the CLR stored proc.
However it looks like, unlike IIS, simply replacing the binaries doesn't work. It seems like you have to DROP ASSEMBLY on the database. In order to do that you need to drop all the objects that reference that assembly.
That seems reasonable in one way -- i.e., from a database integrity point of view-- and unreasonable in another -- the JIT approach that applies for runtime evaluation of dependencies for .NET in general.
So, is it possible to do something so I can replace the binary then give SQL server a kick and make it figure out that the new assembly satisfies all the requirements (i.e., has the right public namespaces, types, methods etc to satisfy the sprocs that are bound to it).
The CLR assemblies are stored in the database, not on disk, so you cannot simply replace some binary dll. To refresh them you use ALTER ASSEMBLY [assemblyname] FROM 'disklocation'.
Short answer is 'No, it will not work this way'. As it was pointed by Remus, SQL Server stores assemblies inside your database and not somewhere in a file system. Thus there's no such place that is monitored by the server and where you should place updated binaries.
Uploading an updated assembly(ies) to the database should be an integral part of your deployment process. And the only way of doing it to perform the following actions explicitly:
Drop all objects that are defined in an assembly (i.e. all external SPs/UDFs/Triggers/Types)
Drop assembly(ies)
Create assembly(ies) - with either "FROM 'disklocation'" (as advised by Remus, but note that the path should refer to SQL Server's local path) or "FROM 'binary content'"
Create all [external] objects
Step 1 can actually be implemented in T-SQL in a generic way (so you don't have to list objects explicitly). But there's not such way for p.4 except custom tool (which will use reflection in order to discover assembly content and generate appropriate T-SQL for creating all objects).
As Remus's answer states, you can use ALTER ASSEMBLY ... to update an assembly.
From the MSDN page ALTER ASSEMBLY (Transact-SQL) for SQL Server 2008 R2 [emphasis mine]:
If the FROM clause is specified, ALTER ASSEMBLY updates the assembly with respect to the latest copies of the modules provided. Because there might be CLR functions, stored procedures, triggers, data types, and user-defined aggregate functions in the instance of SQL Server that are already defined against the assembly, the ALTER ASSEMBLY statement rebinds them to the latest implementation of the assembly. To accomplish this rebinding, the methods that map to CLR functions, stored procedures, and triggers must still exist in the modified assembly with the same signatures. The classes that implement CLR user-defined types and user-defined aggregate functions must still satisfy the requirements for being a user-defined type or aggregate.
So, if the functions, stored procedures, etc. that reference the assembly haven't changed, you can simply update the assembly. Also, doing so doesn't disrupt currently running sessions; from the same MSDN page as mentioned above:
ALTER ASSEMBLY does not disrupt currently running sessions that are running code in the assembly being modified. Current sessions complete execution by using the unaltered bits of the assembly.
However, you could fairly easily re-deploy an assembly and its dependent objects automatically, but to do so generally, you would need to drop and re-create it. If you do so, you may find it easier to deploy the assembly by 'embedding' it in a script by first converting the bytes of the assembly file to hexadecimal digits which can then be included in the relevant CREATE ASSEMBLY statement.
I agree with what AlexS suggested except the last sentence.
First off, reflection will not truly work as the datatypes used in the CLR functions do not necessarily determine the SQL datatypes. For example, you could have SqlString on the CLR side but use NVARCHAR(50) or NVARCHAR(MAX) instead of NVARCHAR(4000) on the SQL side.
However, it is still possible to automate this. You should be using the source code repository to be storing the Stored Proc and Function definitions that point to the CLR code, just as you would any Stored Proc or Function. So you could grab all of those definitions and run all of the CREATE PROCEDURE and CREATE FUNCTION statements as Step 4.
Also, Steps 1 and 2 can be a single SQL script.
Essentially, this entire process can be automated :).

Resources