Related
I have 800+ functions in my database. I would need to modify their source databases dynamically and create snapshots.
example of the function:
create function [schema1].[funTest1] (#param1 varchar(50))
returns table as
return
(
select * from [curr_database1].[schema1].[funTest1](#param1)
union
select * from [curr_database2].[schema1].[funTest1](#param1)
)
I want to change the script as:
create or alter function [schema1].[funTest1] (#param1 varchar(50))
returns table as return
(
select * from [new_database2].[schema1].[funTest1](#param1)
union
select * from [new_database3].[schema1].[funTest1](#param1)
)
basically, I got all the functions script using the sys.syscomments. I'm looking for an option to find and replace the database dynamically to create the snapshots.
How can I get it? Thank you!
Here is the sample code that I have developed for sharing. All the database in the functions starts with the same text(for ex. "curr"). Please share your thoughts. Thanks in advance!
create or alter proc test_proc as
begin
set nocount on
-- this piece of code has the new databases
if object_id('tempdb..#dbNames') is not null drop table #dbNames
create table #dbNames (dbName varchar(1000), id int)
insert into #dbNames(dbName, id) values ('new_database2', 1),('new_database3', 2)
insert into #dbNames(dbName, id) values ('new_database8', 3),('new_database9', 4)
-- this one has the sample functions
if object_id('tempdb..#dbFunctions') is not null drop table #dbFunctions
create table #dbFunctions (funText nvarchar(max))
insert into #dbFunctions (funText) values('create function [schema1].[funTest1] (#param1 varchar(50))
returns table as
return
(
select * from [curr_database1].[schema1].[funTest1](#param1)
union
select * from [curr_database2].[schema1].[funTest1](#param1)
)'),
('create function [schema2].[funTest2] (#param1 varchar(50), #param2 varchar(100))
returns table as
return
(
select * from [curr_database4].[schema2].[funTest2](#param1, #param2)
union
select * from [curr_database5].[schema2].[funTest2](#param1, #param2)
)')
-- declare variables and assign value for #frmStr variable (for testing purposes)
declare #str nvarchar(max)
declare #dbName varchar(100)
declare #frmStr varchar(100) = '[curr_database1]'
-- get the total count of the databases and the functions to iterate and replace the string
declare #dbCnt int = (select count(id) from #dbNames)
declare #fnCnt int = (select count(*) from #dbFunctions)
while #dbCnt > 0
begin
set #dbname = (select dbname from #dbnames where id = #dbcnt)
while #fnCnt > 0
begin
-- this is where I would need to replace the code
select #str = replace(funText, #frmStr, #dbName) from #dbFunctions
select #str
set #fnCnt = #fnCnt - 1
end
set #dbCnt = #dbCnt - 1
end
end
Your actual goal isn't clear, but to answer the question you asked, you can use REPLACE functions in the query to syscomments that you used to get the code in the first place:
REPLACE(
REPLACE([FunctionTextColumn],'curr_database1','new_database2')
,'curr_database2','new_database3'
)
How to achieve below requirement in SQL Server.
Data what I have:
and Expected output is:
Thanks,
Lawrance A
Assuming of your given data value:
'Message:"A",Level:"0",type:"log"'
'Message:"B",Level:"1",type:"log"'
select substring(ColumnA,10,1) Message,
replace(dbo.udf_GetNumeric(replace(replace(substring(ColumnA,20,5),'"',''),',','')),' ','')[type],
replace(replace(substring(ColumnA,29,250),'"',''),',','')[Log] from YourTable
GetNumeric here
I have created two function to achieve your desired output.
use below query by creating two function split and getVal
select
dbo.getVal(columnA,'Message') Message,
dbo.getVal(columnA,'Level') [Level],
dbo.getVal(columnA,'type') [type]
from TableA
Query for creating split and getVal function
Create function split(#s varchar(500),#splitWith varchar(20))
returns #RetTable Table(id int identity(1,1), Value varchar(200))
as
begin
if(CHARINDEX(#splitWith,#s)>0)
begin
set #s=#s+#splitWith
declare #len int =len(#s)
while charindex(#splitWith,#s)>0
begin
insert #RetTable values(SUBSTRING(#s,1,charindex(#splitWith,#s)-1))
set #s=SUBSTRING(#s,charindex(#splitWith,#s,1)+1,#len)
end
end
return
end
Create function getVal(#str varchar(500),#column varchar(200))
returns varchar(200)
as
begin
declare #ret varchar(200)
select #ret=value From dbo.split((select value From dbo.split('Message:"A",Level:"0",type:"log"',',') where value like +#column+'%'),':') where id=2
return replace(#ret,'"','')
end
I want to run a stored procedure on each ID return by a SELECT query. Is there a simple way to do something like:
FOREACH (SELECT ID FROM myTABLE WHERE myName='bob') AS id
BEGIN
EXEC #return_value = [dbo].[spMYPROC]
#PARAM1 = id
#PARAM2 = 0
END
Since I just happened to answer a very similar question yesterday, I have this code handy. As others have stated, it may not be the best approach, but still it's nice to learn how to use a while loop anyway.
Assuming a table named "Customer"
declare #Id int
select #Id = MIN(Id)
from Customer c
while(select COUNT(1)
from Customer c
where c.Id >= #Id) > 0
begin
--run your sproc right here
select #Id = MIN(Id)
from Customer c
where c.Id > #Id
end
DECLARE #ID INT, #return_value INT
DECLARE c CURSOR FOR
SELECT
ID
FROM myTABLE
WHERE myName = 'bob'
OPEN c; FETCH NEXT FROM c INTO #ID
WHILE ##FETCH_STATUS = 0
BEGIN
EXEC #return_value = [dbo].[spMYPROC]
#PARAM1 = #ID,
#PARAM2 = 0
FETCH NEXT FROM c INTO #ID
END
CLOSE c; DEALLOCATE c;
You have two option here
Option 1 Using Split Function
Pass a comma deliminated list of IDs and use a Split function Inside your Procedure to make split these values and do whatever you want to do with it.
To
Make it work you will need two thing
1) Create a Function which
accepts a Comma Deliminated string and split them.
2) Modify you
Store Procedure and add this function in there in a way that passed
parameter is passed to the function inside that store procedure and
that function split the values before passing it onto your store
Procedure .
Create this function 1st
Function Definition
CREATE FUNCTION [dbo].[FnSplit]
(
#List nvarchar(2000),
#SplitOn nvarchar(5)
)
RETURNS #RtnValue table (Id int identity(1,1), Value nvarchar(100))
AS
BEGIN
WHILE(Charindex(#SplitOn,#List)>0)
BEGIN
INSERT INTO #RtnValue (value)
SELECT VALUE = ltrim(rtrim(Substring(#List,1,Charindex(#SplitOn,#List)-1)))
SET #List = SUBSTRING(#List,Charindex(#SplitOn,#List)+len(#SplitOn),len(#List))
END
INSERT INTO #RtnValue (Value)
SELECT VALUE = ltrim(rtrim(#List))
RETURN
END
Modify you strored Procedure something like this
Stored Procedure
ALTER Procedure [dbo].[spMYPROC] (#Param1 VARCHAR(1000)= NULL)
AS
BEGIN
SELECT * FROM TableName
where ColumnNAME IN (SELECT Value FROM dbo.FnSplit(#Param1,','))
END
GO
Option 2 Table Type Parameter
Create a Table Type and alter your proc to accept a Table Type Parameter and do whatever you want to do with them values inside your proc.
TABLE TYPE
CREATE TYPE dbo.TYPENAME AS TABLE
(
Value int
)
GO
Stored Procedure to Accept That Type Param
ALTER PROCEDURE [dbo].[spMYPROC]
#TableParam TYPENAME READONLY
AS
BEGIN
SET NOCOUNT ON;
--Temp table to store passed Id values
declare #tmp_values table (value INT );
--Insert passed values to a table variable inside the proc
INSERT INTO #tmp_values (value)
SELECT Value FROM #TableParam
/* Do your stuff here whatever you want to do with Ids */
END
EXECUTE PROC
Declare a variable of that type and populate it with your values.
DECLARE #Table TYPENAME --<-- Variable of this TYPE
INSERT INTO #Table --<-- Populating the variable
SELECT ID FROM myTABLE WHERE myName='bob'
EXECUTE [dbo].[spMYPROC] #Table --<-- Stored Procedure Executed
i am exporting some date to sql server using string builder.and here i assign all the values to particular tables.but i don't know i got some error.i can't resolve.help me to resolve this.
ALTER PROCEDURE [dbo].[usp_CreateEmployeDetails]
#nEmployeeDetailsInXML nvarchar(max)=''
As
DECLARE #iTree INTEGER
declare #empid int
BEGIN
SET NOCOUNT ON;
create table #TempRelation(RowNo int identity(1,1),RelationShipId int,RelativeName nvarchar(100),DOB date,IsNominee bit)
create table #Temp_Present_Address(RowNo int identity(1,1),Street1 nvarchar(200),Street2 nvarchar(200),CountryId int,StateId int,CityId int,AddressTypeId int)
create table #Temp_Permanent_Address(RowNo int identity(1,1),Street1 nvarchar(200),Street2 nvarchar(200),CountryId int,StateId int,CityId int,AddressTypeId int)
create table #TempDetails(RowNo int identity(1,1),EmployeeName nvarchar(100),DOB date,DOJ date,Email nvarchar(100),Phone bigint,BoodGroup nchar(10),
PAN_No nvarchar(15),PF_No nvarchar(100),Sex char(10),AccountNo nvarchar(100),BankName nvarchar(100),BranchId int,ManagerId int,HrId int,DesigId int)
exec sp_xml_preparedocument #iTree output,#nEmployeeDetailsInXML
insert into #TempRelation(RelationShipId,RelativeName,DOB,IsNominee)
select RelationShipId,RelativeName,DOB,IsNominee
from openxml (#iTree,'EmployeeDetails/EmployeeRelation',1)
with(RelationShipId int,RelativeName nvarchar(100),DOB date,IsNominee bit)
insert into #Temp_Permanent_Address(Street1,Street2,CountryId,StateId,CityId,AddressTypeId)
select Street1,Street2,CountryId,StateId,CityId,AddressTypeId
from openxml (#iTree,'EmployeeDetails/EmployeePermanentAdress',1)
with(Street1 nvarchar(200),Street2 nvarchar(200),CountryId int,StateId int,CityId int,AddressTypeId int)
insert into #Temp_Present_Address(Street1,Street2,CountryId,StateId,CityId,AddressTypeId)
select Street1,Street2,CountryId,StateId,CityId,AddressTypeId
from openxml (#iTree,'EmployeeDetails/EmployeePresentAdress',1)
with(Street1 nvarchar(200),Street2 nvarchar(200),CountryId int,StateId int,CityId int,AddressTypeId int)
insert into #TempDetails(EmployeeName,DOB,DOJ,Email,Phone,BoodGroup,PAN_No,PF_No,Sex,AccountNo,BankName,BranchId,ManagerId,HrId,DesigId)
select EmployeeName,DOB,DOJ,Email,Phone,BoodGroup,PAN_No,PF_No,Sex,AccountNo,BankName,BranchId,ManagerId,HrId,DesigId
from openxml (#iTree,'EmployeeDetails/Employee',1)
with(EmployeeName nvarchar(100),DOB date,DOJ date,Email nvarchar(100),Phone bigint,BoodGroup nchar(10),PAN_No nvarchar(15),PF_No nvarchar(100),Sex char(10),
AccountNo nvarchar(100),BankName nvarchar(100),BranchId int,ManagerId int,HrId int,DesigId int)
if((select COUNT(RowNo) from #TempDetails)>0)
begin
insert into Employee(EmployeeName,DOB,DOJ,Email,Phone,BoodGroup,PAN_No,PF_No,Sex)output inserted.EmployeeId select EmployeeName,DOB,DOJ,Email,Phone,BoodGroup,PAN_No,PF_No,Sex from #TempDetails
set #empid=SCOPE_IDENTITY()
if((select COUNT(EmployeeName) from Employee where EmployeeId=#empid)>0)
begin
insert into EmployeeAccountDetls(EmployeeId,AccountNo,BankName)values(#empid,(select AccountNo,BankName from #TempDetails))
insert into EmployeeLink(EmployeeId,BranchId,ManagerId,HrId,DesigId)values(#empid,(select BranchId,ManagerId,HrId,DesigId from #TempDetails))
if((select COUNT(RowNo) from #Temp_Permanent_Address)>0)
begin
insert into EmployeeAddress(EmployeeId,Street1,Street2,CountryId,StateId,CityId,AddressTypeId)values(#empid,(select Street1,Street2,CountryId,StateId,CityId,AddressTypeId from #Temp_Permanent_Address))
end
if((select COUNT(RowNo) from #Temp_Present_Address)>0)
begin
insert into EmployeeAddress(EmployeeId,Street1,Street2,CountryId,StateId,CityId,AddressTypeId)values(#empid,(select Street1,Street2,CountryId,StateId,CityId,AddressTypeId from #Temp_Present_Address))
end
if((select COUNT(RowNo) from #TempRelation)>0)
begin
insert into EmployeeRelationDetls(EmployeeId,RelationShipId,RelativeName,DOB,isNominee)values(#empid,(select RelationShipId,RelativeName,DOB,IsNominee from #TempRelation))
end
end
end
EXEC sp_xml_removedocument #iTree
drop table #Temp_Present_Address
drop table #Temp_Permanent_Address
drop table #TempDetails
drop table #TempRelation
END
why its happening i checked but i didn't get the result
For the specific error you mention, your problem is here:
insert into EmployeeAddress(EmployeeId,Street1,Street2,CountryId,StateId,CityId,AddressTypeId)
values (#empid, (select Street1,Street2,CountryId,StateId,CityId,AddressTypeId from #Temp_Permanent_Address))
You probably want:
insert into EmployeeAddress(EmployeeId,Street1,Street2,CountryId,StateId,CityId,AddressTypeId)
SELECT #empid,Street1,Street2,CountryId,StateId,CityId,AddressTypeId from #Temp_Permanent_Address
However, you're inserting multiple rows and then giving the last rows IDENTITY value to every address row doing that. You need to find a better way of relating keys - which can either be done using MERGE's output clause or by using a stronger key to reference back to the table you just inserted into in order to find the newly inserted employee ID.
Is there a way to make a TSQL variable constant?
No, but you can create a function and hardcode it in there and use that.
Here is an example:
CREATE FUNCTION fnConstant()
RETURNS INT
AS
BEGIN
RETURN 2
END
GO
SELECT dbo.fnConstant()
One solution, offered by Jared Ko is to use pseudo-constants.
As explained in SQL Server: Variables, Parameters or Literals? Or… Constants?:
Pseudo-Constants are not variables or parameters. Instead, they're simply views with one row, and enough columns to support your constants. With these simple rules, the SQL Engine completely ignores the value of the view but still builds an execution plan based on its value. The execution plan doesn't even show a join to the view!
Create like this:
CREATE SCHEMA ShipMethod
GO
-- Each view can only have one row.
-- Create one column for each desired constant.
-- Each column is restricted to a single value.
CREATE VIEW ShipMethod.ShipMethodID AS
SELECT CAST(1 AS INT) AS [XRQ - TRUCK GROUND]
,CAST(2 AS INT) AS [ZY - EXPRESS]
,CAST(3 AS INT) AS [OVERSEAS - DELUXE]
,CAST(4 AS INT) AS [OVERNIGHT J-FAST]
,CAST(5 AS INT) AS [CARGO TRANSPORT 5]
Then use like this:
SELECT h.*
FROM Sales.SalesOrderHeader h
JOIN ShipMethod.ShipMethodID const
ON h.ShipMethodID = const.[OVERNIGHT J-FAST]
Or like this:
SELECT h.*
FROM Sales.SalesOrderHeader h
WHERE h.ShipMethodID = (SELECT TOP 1 [OVERNIGHT J-FAST] FROM ShipMethod.ShipMethodID)
My workaround to missing constans is to give hints about the value to the optimizer.
DECLARE #Constant INT = 123;
SELECT *
FROM [some_relation]
WHERE [some_attribute] = #Constant
OPTION( OPTIMIZE FOR (#Constant = 123))
This tells the query compiler to treat the variable as if it was a constant when creating the execution plan. The down side is that you have to define the value twice.
No, but good old naming conventions should be used.
declare #MY_VALUE as int
There is no built-in support for constants in T-SQL. You could use SQLMenace's approach to simulate it (though you can never be sure whether someone else has overwritten the function to return something else…), or possibly write a table containing constants, as suggested over here. Perhaps write a trigger that rolls back any changes to the ConstantValue column?
Prior to using a SQL function run the following script to see the differences in performance:
IF OBJECT_ID('fnFalse') IS NOT NULL
DROP FUNCTION fnFalse
GO
IF OBJECT_ID('fnTrue') IS NOT NULL
DROP FUNCTION fnTrue
GO
CREATE FUNCTION fnTrue() RETURNS INT WITH SCHEMABINDING
AS
BEGIN
RETURN 1
END
GO
CREATE FUNCTION fnFalse() RETURNS INT WITH SCHEMABINDING
AS
BEGIN
RETURN ~ dbo.fnTrue()
END
GO
DECLARE #TimeStart DATETIME = GETDATE()
DECLARE #Count INT = 100000
WHILE #Count > 0 BEGIN
SET #Count -= 1
DECLARE #Value BIT
SELECT #Value = dbo.fnTrue()
IF #Value = 1
SELECT #Value = dbo.fnFalse()
END
DECLARE #TimeEnd DATETIME = GETDATE()
PRINT CAST(DATEDIFF(ms, #TimeStart, #TimeEnd) AS VARCHAR) + ' elapsed, using function'
GO
DECLARE #TimeStart DATETIME = GETDATE()
DECLARE #Count INT = 100000
DECLARE #FALSE AS BIT = 0
DECLARE #TRUE AS BIT = ~ #FALSE
WHILE #Count > 0 BEGIN
SET #Count -= 1
DECLARE #Value BIT
SELECT #Value = #TRUE
IF #Value = 1
SELECT #Value = #FALSE
END
DECLARE #TimeEnd DATETIME = GETDATE()
PRINT CAST(DATEDIFF(ms, #TimeStart, #TimeEnd) AS VARCHAR) + ' elapsed, using local variable'
GO
DECLARE #TimeStart DATETIME = GETDATE()
DECLARE #Count INT = 100000
WHILE #Count > 0 BEGIN
SET #Count -= 1
DECLARE #Value BIT
SELECT #Value = 1
IF #Value = 1
SELECT #Value = 0
END
DECLARE #TimeEnd DATETIME = GETDATE()
PRINT CAST(DATEDIFF(ms, #TimeStart, #TimeEnd) AS VARCHAR) + ' elapsed, using hard coded values'
GO
If you are interested in getting optimal execution plan for a value in the variable you can use a dynamic sql code. It makes the variable constant.
DECLARE #var varchar(100) = 'some text'
DECLARE #sql varchar(MAX)
SET #sql = 'SELECT * FROM table WHERE col = '''+#var+''''
EXEC (#sql)
For enums or simple constants, a view with a single row has great performance and compile time checking / dependency tracking ( cause its a column name )
See Jared Ko's blog post https://blogs.msdn.microsoft.com/sql_server_appendix_z/2013/09/16/sql-server-variables-parameters-or-literals-or-constants/
create the view
CREATE VIEW ShipMethods AS
SELECT CAST(1 AS INT) AS [XRQ - TRUCK GROUND]
,CAST(2 AS INT) AS [ZY - EXPRESS]
,CAST(3 AS INT) AS [OVERSEAS - DELUXE]
, CAST(4 AS INT) AS [OVERNIGHT J-FAST]
,CAST(5 AS INT) AS [CARGO TRANSPORT 5]
use the view
SELECT h.*
FROM Sales.SalesOrderHeader
WHERE ShipMethodID = ( select [OVERNIGHT J-FAST] from ShipMethods )
Okay, lets see
Constants are immutable values which are known at compile time and do not change for the life of the program
that means you can never have a constant in SQL Server
declare #myvalue as int
set #myvalue = 5
set #myvalue = 10--oops we just changed it
the value just changed
Since there is no build in support for constants, my solution is very simple.
Since this is not supported:
Declare Constant #supplement int = 240
SELECT price + #supplement
FROM what_does_it_cost
I would simply convert it to
SELECT price + 240/*CONSTANT:supplement*/
FROM what_does_it_cost
Obviously, this relies on the whole thing (the value without trailing space and the comment) to be unique. Changing it is possible with a global search and replace.
There are no such thing as "creating a constant" in database literature. Constants exist as they are and often called values. One can declare a variable and assign a value (constant) to it. From a scholastic view:
DECLARE #two INT
SET #two = 2
Here #two is a variable and 2 is a value/constant.
SQLServer 2022 (currently only as Preview available) is now able to Inline the function proposed by SQLMenace, this should prevent the performance hit described by some comments.
CREATE FUNCTION fnConstant() RETURNS INT AS BEGIN RETURN 2 END GO
SELECT is_inlineable FROM sys.sql_modules WHERE [object_id]=OBJECT_ID('dbo.fnConstant');
is_inlineable
1
SELECT dbo.fnConstant()
ExecutionPlan
To test if it also uses the value coming from the Function, I added a second function returning value "1"
CREATE FUNCTION fnConstant1()
RETURNS INT
AS
BEGIN
RETURN 1
END
GO
Create Temp Table with about 500k rows with Value 1 and 4 rows with Value 2:
DROP TABLE IF EXISTS #temp ;
create table #temp (value_int INT)
DECLARE #counter INT;
SET #counter = 0
WHILE #counter <= 500000
BEGIN
INSERT INTO #temp VALUES (1);
SET #counter = #counter +1
END
SET #counter = 0
WHILE #counter <= 3
BEGIN
INSERT INTO #temp VALUES (2);
SET #counter = #counter +1
END
create index i_temp on #temp (value_int);
Using the describe plan we can see that the Optimizer expects 500k values for
select * from #temp where value_int = dbo.fnConstant1(); --Returns 500001 rows
Constant 1
and 4 rows for
select * from #temp where value_int = dbo.fnConstant(); --Returns 4rows
Constant 2
Robert's performance test is interesting. And even in late 2022, the scalar functions are much slower (by an order of magnitude) than variables or literals. A view (as suggested mbobka) is somewhere in-between when used for this same test.
That said, using a loop like that in SQL Server is not something I'd ever do, because I'd normally be operating on a whole set.
In SQL 2019, if you use schema-bound functions in a set operation, the difference is much less noticeable.
I created and populated a test table:
create table #testTable (id int identity(1, 1) primary key, value tinyint);
And changed the test so that instead of looping and changing a variable, it queries the test table and returns true or false depending on the value in the test table, e.g.:
insert #testTable(value)
select case when value > 127
then #FALSE
else #TRUE
end
from #testTable with(nolock)
I tested 5 scenarios:
hard-coded values
local variables
scalar functions
a view
a table-valued function
running the test 10 times, yielded the following results:
scenario
min
max
avg
scalar functions
233
259
240
hard-coded values
236
265
243
local variables
235
278
245
table-valued function
243
272
253
view
244
267
254
Suggesting to me, that for set-based work in (at least) 2019 and better, there's not much in it.
set nocount on;
go
-- create test data table
drop table if exists #testTable;
create table #testTable (id int identity(1, 1) primary key, value tinyint);
-- populate test data
insert #testTable (value)
select top (1000000) convert(binary (1), newid())
from sys.all_objects a
, sys.all_objects b
go
-- scalar function for True
drop function if exists fnTrue;
go
create function dbo.fnTrue() returns bit with schemabinding as
begin
return 1
end
go
-- scalar function for False
drop function if exists fnFalse;
go
create function dbo.fnFalse () returns bit with schemabinding as
begin
return 0
end
go
-- table-valued function for booleans
drop function if exists dbo.tvfBoolean;
go
create function tvfBoolean() returns table with schemabinding as
return
select convert(bit, 1) as true, convert(bit, 0) as false
go
-- view for booleans
drop view if exists dbo.viewBoolean;
go
create view dbo.viewBoolean with schemabinding as
select convert(bit, 1) as true, convert(bit, 0) as false
go
-- create table for results
drop table if exists #testResults
create table #testResults (id int identity(1,1), test int, elapsed bigint, message varchar(1000));
-- define tests
declare #tests table(testNumber int, description nvarchar(100), sql nvarchar(max))
insert #tests values
(1, N'hard-coded values', N'
declare #testTable table (id int, value bit);
insert #testTable(id, value)
select id, case when t.value > 127
then 0
else 1
end
from #testTable t')
, (2, N'local variables', N'
declare #FALSE as bit = 0
declare #TRUE as bit = 1
declare #testTable table (id int, value bit);
insert #testTable(id, value)
select id, case when t.value > 127
then #FALSE
else #TRUE
end
from #testTable t'),
(3, N'scalar functions', N'
declare #testTable table (id int, value bit);
insert #testTable(id, value)
select id, case when t.value > 127
then dbo.fnFalse()
else dbo.fnTrue()
end
from #testTable t'),
(4, N'view', N'
declare #testTable table (id int, value bit);
insert #testTable(id, value)
select id, case when value > 127
then b.false
else b.true
end
from #testTable t with(nolock), viewBoolean b'),
(5, N'table-valued function', N'
declare #testTable table (id int, value bit);
insert #testTable(id, value)
select id, case when value > 127
then b.false
else b.true
end
from #testTable with(nolock), dbo.tvfBoolean() b')
;
declare #testNumber int, #description varchar(100), #sql nvarchar(max)
declare #testRuns int = 10;
-- execute tests
while #testRuns > 0 begin
set #testRuns -= 1
declare testCursor cursor for select testNumber, description, sql from #tests;
open testCursor
fetch next from testCursor into #testNumber, #description, #sql
while ##FETCH_STATUS = 0 begin
declare #TimeStart datetime2(7) = sysdatetime();
execute sp_executesql #sql;
declare #TimeEnd datetime2(7) = sysdatetime()
insert #testResults(test, elapsed, message)
select #testNumber, datediff_big(ms, #TimeStart, #TimeEnd), #description
fetch next from testCursor into #testNumber, #description, #sql
end
close testCursor
deallocate testCursor
end
-- display results
select test, message, count(*) runs, min(elapsed) as min, max(elapsed) as max, avg(elapsed) as avg
from #testResults
group by test, message
order by avg(elapsed);
The best answer is from SQLMenace according to the requirement if that is to create a temporary constant for use within scripts, i.e. across multiple GO statements/batches.
Just create the procedure in the tempdb then you have no impact on the target database.
One practical example of this is a database create script which writes a control value at the end of the script containing the logical schema version. At the top of the file are some comments with change history etc... But in practice most developers will forget to scroll down and update the schema version at the bottom of the file.
Using the above code allows a visible schema version constant to be defined at the top before the database script (copied from the generate scripts feature of SSMS) creates the database but used at the end. This is right in the face of the developer next to the change history and other comments, so they are very likely to update it.
For example:
use tempdb
go
create function dbo.MySchemaVersion()
returns int
as
begin
return 123
end
go
use master
go
-- Big long database create script with multiple batches...
print 'Creating database schema version ' + CAST(tempdb.dbo.MySchemaVersion() as NVARCHAR) + '...'
go
-- ...
go
-- ...
go
use MyDatabase
go
-- Update schema version with constant at end (not normally possible as GO puts
-- local #variables out of scope)
insert MyConfigTable values ('SchemaVersion', tempdb.dbo.MySchemaVersion())
go
-- Clean-up
use tempdb
drop function MySchemaVersion
go