Serializing access to a table row in HANA - hana

Whereas I am not allowed to use either identity columns or HANA sequences, I am forced manually to generate unique autoincrementing keys for tables. Here is my unsafe and naive key generation procedure, which stores unique counters in table TABLEKEYS and increments them at every execution:
CREATE PROCEDURE NewKey
( IN SeqName NVARCHAR( 32),
OUT NewKey BIGINT
)
AS rec_exists INT;
row_num INT;
BEGIN
SELECT SUM(1) INTO rec_exists
FROM ( SELECT TOP 1 1 FROM TABLEKEYS WHERE "Name" = :SeqName ) T;
IF :rec_exists IS NULL THEN
SELECT COALESCE(SUM(1),0) INTO row_num FROM TABLEKEYS;
INSERT INTO TABLEKEYS("Code", "Name", "U_CurrentKey")
VALUES (row_num, :SeqName, -1 );
END IF;
UPDATE TABLEKEYS SET "U_CurrentKey" = "U_CurrentKey" + 1
WHERE "Name" = :SeqName;
SELECT "CurrentKey" INTO NewKey FROM TABLEKEYS
WHERE "Name" = :SeqName;
END;
How to make it reliable, so that it shall not return two identical keys under any circumstances, even when it is being called intensively from an hundred simultaneous connections? In MSSQL Server I should wrap its body in a transaction and apply locking hints to the table in the initial query, but I am not aware of their analogs in HANA. Is there a way in HANA to ensure that a table row is accessed strictly sequencially?
My procedure with corrections suggested by Lars and adapted for Business One user-defined tables:
CREATE PROCEDURE GTGetNewKeyInt
( IN TableName NVARCHAR( 32),
OUT NewKey BIGINT
)
AS cur_key INT;
row_num INT;
row_num_txt VARCHAR(8);
BEGIN
BEGIN
DECLARE EXIT HANDLER FOR SQLEXCEPTION
BEGIN
END;
SELECT "U_CurrentKey" INTO cur_key FROM "#GTTABLEKEYS"
WHERE "Name" = :TableName
FOR UPDATE;
END;
IF :cur_key IS NULL THEN
LOCK TABLE "#GTTABLEKEYS" IN EXCLUSIVE MODE;
SELECT COALESCE(SUM(1),0) INTO row_num FROM "#GTTABLEKEYS";
row_num_txt = LPAD( CAST( row_num AS varchar ), 8, '0' );
NewKey = 0;
INSERT INTO "#GTTABLEKEYS"("Code", "Name", "U_CurrentKey")
VALUES (row_num_txt, :TableName, :NewKey );
ELSE
NewKey = :cur_key + 1;
UPDATE "#GTTABLEKEYS" SET "U_CurrentKey" = :NewKey
WHERE "Name" = :TableName;
END IF;
END;

First off: not using the built-in features like sequences or the IDENTITY column seems rather not like a great idea.
Anything you build yourself here, will be inferior in one or the other regard.
But, hey, it's your code after all.
So, for selecting with locking, there is the standard SQL command
SELECT ... FOR UPDATE FROM...
(also see the documentation here)
Your program logic will be to
SELECT ... FOR UPDATE
do whatever you have to do
Update the sequence table
COMMIT or ROLLBACK
Your record will be locked as of step 1.
In order to make the whole process more efficient and to decouple the performance for managing the sequence from the amount of data in the actual data table, you may want to keep the sequence in its own table (row store might be a good idea for this one, as you deal with a single record and lots of updates). That's rather close to how sequences work as well.

Related

SQL Stored Procedure Simultaneously Call Issue

I have stored procedure in the sql server 2008, my stored procedure calculate and get the last number "not primary key" from column from table B and add one ( +1 ) to this number to use it on the next statement on the same stored procedure.
My issue that i have a duplicate number some times, i think this happened when multiple users call the stored procedure on the same time. is this the issue and how can i solve it
my code is like the below:-
DECLARE #ID AS NVARCHAR(10)
SET #ID = (
SELECT TOP 1 MyNo
FROM Employee
WHERE (
(TypeID = #TypeID) AND
(Year = #Year)
)
ORDER BY ID DESC
)
SET #ID = ISNULL(#ID,0) + 1
INSERT INTO Employee (name,lname,MyNo) VALUES (#name,#lname,#MyNo)
You can lock a table for the duration of a transaction with the WITH (TABLOCKX, HOLDLOCK) syntax:
BEGIN TRANSACTION
DECLARE #ID AS NVARCHAR(10)
SET #ID = (
SELECT TOP 1 MyNo
FROM Employee WITH (TABLOCKX, HOLDLOCK)
WHERE (
(TypeID = #TypeID) AND
(Year = #Year)
)
ORDER BY ID DESC
)
SET #ID = ISNULL(#ID,0) + 1
INSERT INTO Employee (name,lname,MyNo) VALUES (#name,#lname,#MyNo)
COMMIT TRANSACTION
You can find more information about TABLOCK and TABLOCKX here:
https://learn.microsoft.com/en-us/sql/t-sql/queries/hints-transact-sql-table
Per discussion, the best lock to use in this case would be:
(UPDLOCK,HOLDLOCK)
If you cannot use Identity column or the Table lock, another alternative is to use sp_getapplock
The advantage with this mechanism is that this kind of lock can be used across multiple stored procedures that should not run concurrently or for operations that span multiple tables. It also allows for handling timeout and other kinds of behavior if the lock is not available.
You have to be careful when using this feature and ensure you acquire and release locks properly or you will create more problems than you solve.

SQL Server Table Locking

I need to create a unique identifier for clients, I'm implementing this using a 9 digit Luhn (9th digit being the checkdigit), so I can validate its authenticity. The numbers I want to generate are random, so I create an 8 digit number and work out the check digit to go with it, that's all great.
My problem is that I need to check that it doesn't already exist in my client table. I have added an index to ensure duplicate values can't be inserted, but am looking for a steer on how to lock the table involved within the transaction I've created to ensure no concurrency issues arise, i.e. can't attempt to insert a duplicate.
Any suggestions on approach or recommendations welcome, I know this is probably a noddy question.
The short answer is that you don't have direct control over which type of lock is used and when. You do have the ability, however, to place multiple statements within an explicitly defined transaction.
At the end of the transaction, you can check to see if there were errors in processing or if your data is in an invalid state. Then you would commit if everything is fine or rollback if not. But, beware of leaving transactions open! If you don't commit or rollback your transaction, the affected tables will remain locked and all transactions against those tables will be blocked until you either commit or rollback the transaction.
Here is an example that will hopefully be of help:
DECLARE #Table TABLE
(
ID INT IDENTITY PRIMARY KEY
,Luhn INT
,UNIQUE(Luhn)
)
DECLARE #MaxTries INT = 10;
DECLARE #Try INT = 1;
DECLARE #Luhn INT;
DECLARE #IsLuhnAvailable BIT = 0;
BEGIN TRAN;
WHILE #IsLuhnAvailable = 0 AND #Try <= #MaxTries
BEGIN
SET #Luhn = CHECKSUM(NEWID()); --dbo.GenerateLuhn()
SET #IsLuhnAvailable = CASE WHEN EXISTS ( SELECT 1 FROM #Table WHERE Luhn = #Luhn ) THEN 0 ELSE 1 END;
SET #Try +=1;
END
IF #IsLuhnAvailable = 0
BEGIN
PRINT 'Luhn could not be generated.'
ROLLBACK;
END
ELSE
BEGIN
INSERT INTO #Table
(
Luhn
)
VALUES
(
#Luhn
)
PRINT 'New Luhn was generated: ' + CAST(#Luhn AS VARCHAR)
COMMIT;
END
SELECT * FROM #Table

Generating the Next Id when Id is non-AutoNumber

I have a table called Employee. The EmpId column serves as the primary key. In my scenario, I cannot make it AutoNumber.
What would be the best way of generating the the next EmpId for the new row that I want to insert in the table?
I am using SQL Server 2008 with C#.
Here is the code that i am currently getting, but to enter Id's in key value pair tables or link tables (m*n relations)
Create PROCEDURE [dbo].[mSP_GetNEXTID]
#NEXTID int out,
#TABLENAME varchar(100),
#UPDATE CHAR(1) = NULL
AS
BEGIN
DECLARE #QUERY VARCHAR(500)
BEGIN
IF EXISTS (SELECT LASTID FROM LASTIDS WHERE TABLENAME = #TABLENAME and active=1)
BEGIN
SELECT #NEXTID = LASTID FROM LASTIDS WHERE TABLENAME = #TABLENAME and active=1
IF(#UPDATE IS NULL OR #UPDATE = '')
BEGIN
UPDATE LASTIDS
SET LASTID = LASTID + 1
WHERE TABLENAME = #TABLENAME
and active=1
END
END
ELSE
BEGIN
SET #NEXTID = 1
INSERT INTO LASTIDS(LASTID,TABLENAME, ACTIVE)
VALUES(#NEXTID+1,#TABLENAME, 1)
END
END
END
Using MAX(id) + 1 is a bad idea both performance and concurrency wise.
Instead you should resort to sequences which were design specifically for this kind of problem.
CREATE SEQUENCE EmpIdSeq AS bigint
START WITH 1
INCREMENT BY 1;
And to generate the next id use:
SELECT NEXT VALUE FOR EmpIdSeq;
You can use the generated value in a insert statement:
INSERT Emp (EmpId, X, Y)
VALUES (NEXT VALUE FOR EmpIdSeq, 'x', 'y');
And even use it as default for your column:
CREATE TABLE Emp
(
EmpId bigint PRIMARY KEY CLUSTERED
DEFAULT (NEXT VALUE FOR EmpIdSeq),
X nvarchar(255) NULL,
Y nvarchar(255) NULL
);
Update: The above solution is only applicable to SQL Server 2012+. For older versions you can simulate the sequence behavior using dummy tables with identity fields:
CREATE TABLE EmpIdSeq (
SeqID bigint IDENTITY PRIMARY KEY CLUSTERED
);
And procedures that emulates NEXT VALUE:
CREATE PROCEDURE GetNewSeqVal_Emp
#NewSeqVal bigint OUTPUT
AS
BEGIN
SET NOCOUNT ON
INSERT EmpIdSeq DEFAULT VALUES
SET #NewSeqVal = scope_identity()
DELETE FROM EmpIdSeq WITH (READPAST)
END;
Usage exemple:
DECLARE #NewSeqVal bigint
EXEC GetNewSeqVal_Emp #NewSeqVal OUTPUT
The performance overhead of deleting the last inserted element will be minimal; still, as pointed out by the original author, you can optionally remove the delete statement and schedule a maintenance job to delete the table contents off-hour (trading space for performance).
Adapted from SQL Server Customer Advisory Team Blog.
Working SQL Fiddle
The above
select max(empid) + 1 from employee
is the way to get the next number, but if there are multiple user inserting into the database, then context switching might cause two users to get the same value for empid and then add 1 to each and then end up with repeat ids. If you do have multiple users, you may have to lock the table while inserting. This is not the best practice and that is why the auto increment exists for database tables.
I hope this works for you. Considering that your ID field is an integer
INSERT INTO Table WITH (TABLOCK)
(SELECT CASE WHEN MAX(ID) IS NULL
THEN 1 ELSE MAX(ID)+1 END FROM Table), VALUE_1, VALUE_2....
Try following query
INSERT INTO Table VALUES
((SELECT isnull(MAX(ID),0)+1 FROM Table), VALUE_1, VALUE_2....)
you have to check isnull in on max values otherwise it will return null in final result when table contain no rows .

Does anyone know a neat trick for reusing identity values?

Typically when you specify an identity column you get a convenient interface in SQL Server for asking for particular row.
SELECT * FROM $IDENTITY = #pID
You don't really need to concern yourself with the name if the identity column because there can only be one.
But what if I have a table which mostly consists of temporary data. Lots of inserts and lots of deletes. Is there a simple way for me to reuse the identity values.
Preferably I would want to be able to write a function that would return say NEXT_SMALLEST($IDENTITY) as next identity value and do so in a fail-safe manner.
Basically find the smallest value that's not in use. That's not entirely trivial to do, but what I want is to be able to tell SQL Server that this is my function that will generate the identity values. But what I know is that no such function exists...
I want to...
Implement global data base IDs, I need to provide a default value that I'm in control of.
My idea was based around that I should be able to have a table with all known IDs and then every row ID from some other table that needed a global ID would reference that table. The default value would be provided by something like
INSERT INTO GlobalID
RETURN SCOPE_IDENTITY()
No; it's not unique if it can be reused.
Why do you want to re-use them? Why do you concern yourself with this field? If you want to be in control of it, don't make it an identity; create your own scheme and use that.
Don't reuse identities, you'll just shoot your self in the foot. Use a large enough value so that it never rolls over (64 bit big int).
To find missing gaps in a sequence of numbers join the table against itself with a +/- 1 difference:
SELECT a.id
FROM table AS a
LEFT OUTER JOIN table AS b ON a.id = b.id+1
WHERE b.id IS NULL;
This query will find the numbers in the id sequence for which id-1 is not in the table, ie. contiguous sequence start numbers. You can then use SET IDENTITY INSERT OFF to insert a specific id and reuse a number. The cost of doing so is overwhelming (both runtime and code complexity) compared with the an ordinary identity based insert.
If you really want to reset Identity value to the lowest,
here is the trick you can use through DBCC CHECKIDENT
Basically following sql statements resets identity value so that identity value restarts from the lowest possible number
create table TT (id int identity(1, 1))
GO
insert TT default values
GO 10
select * from TT
GO
delete TT where id between 5 and 10
GO
--; At this point, next ID will be 11, not 5
select * from TT
GO
insert TT default values
GO
--; as you can see here, next ID is indeed 11
select * from TT
GO
--; Now delete ID = 11
--; so that we can reseed next highest ID to 5
delete TT where id = 11
GO
--; Now, let''s reseed identity value to the lowest possible identity number
declare #seedID int
select #seedID = max(id) from TT
print #seedID --; 4
--; We reseed identity column with "DBCC CheckIdent" and pass a new seed value
--; But we can't pass a seed number as argument, so let's use dynamic sql.
declare #sql nvarchar(200)
set #sql = 'dbcc checkident(TT, reseed, ' + cast(#seedID as varchar) + ')'
exec sp_sqlexec #sql
GO
--; Now the next
insert TT default values
GO
--; as you can see here, next ID is indeed 5
select * from TT
GO
I guess we would really need to know why you want to reuse your identity column. The only reason I can think of is because of the temporary nature of your data you might exhaust the possible values for the identity. That is not really likely, but if that is your concern, you can use uniqueidentifiers (guids) as the primary key in your table instead.
The function newid() will create a new guid and can be used in insert statements (or other statements). Then when you delete the row, you don't have any "holes" in your key because guids are not created in that order anyway.
[Syntax assumes SQL2008....]
Yes, it's possible. You need to two management tables, and two triggers on each participating table.
First, the management tables:
-- this table should only ever have one row
CREATE TABLE NextId (Id INT)
INSERT NextId VALUES (1)
GO
CREATE TABLE RecoveredIds (Id INT NOT NULL PRIMARY KEY)
GO
Then, the triggers, two on each table:
CREATE TRIGGER tr_TableName_RecoverId ON TableName
FOR DELETE AS BEGIN
IF ##ROWCOUNT = 0 RETURN
INSERT RecoveredIds (Id) SELECT Id FROM deleted
END
GO
CREATE TRIGGER tr_TableName_AssignId ON TableName
INSTEAD OF INSERT AS BEGIN
DECLARE #rowcount INT = ##ROWCOUNT
IF #rowcount = 0 RETURN
DECLARE #required INT = #rowcount
DECLARE #new_ids TABLE (Id INT PRIMARY KEY)
DELETE TOP (#required) OUTPUT DELETED.Id INTO #new_ids (Id) FROM RecoveredIds
SET #rowcount = ##ROWCOUNT
IF #rowcount < #required BEGIN
DECLARE #output TABLE (Id INT)
UPDATE NextId SET Id = Id + (#required-#rowcount)
OUTPUT DELETED.Id INTO #output
-- this assumes you have a numbers table around somewhere
INSERT #new_ids (Id)
SELECT n.Number+o.Id-1 FROM Numbers n, #output o
WHERE n.Number BETWEEN 1 AND #required-#rowcount
END
SET IDENTITY_INSERT TableName ON
;WITH inserted_CTE AS (SELECT _no = ROW_NUMBER() OVER (ORDER BY Id), * FROM inserted)
, new_ids_CTE AS (SELECT _no = ROW_NUMBER() OVER (ORDER BY Id), * FROM #new_ids)
INSERT TableName (Id, Attr1, Attr2)
SELECT n.Id, i.Attr1, i.Attr2
FROM inserted_CTE i JOIN new_ids_CTE n ON i._no = n._no
SET IDENTITY_INSERT TableName OFF
END
You could script the triggers out easily enough from system tables.
You would want to test this for concurrency. It should work as is, syntax errors notwithstanding: The OUTPUT clause guarantees atomicity of id lookup->increment as one step, and the entire operation occurs within a transaction, thanks to the trigger.
TableName.Id is still an identity column. All the common idioms like $IDENTITY and SCOPE_IDENTITY() will still work.
There is no central table of ids by table, but you could create one easily enough.
I don't have any help for finding the values not in use but if you really want to find them and set them yourself, you can use
set identity_insert on ....
in your code to do so.
I'm with everyone else though. Why bother? Don't you have a business problem to solve?

Possible to implement a manual increment with just simple SQL INSERT?

I have a primary key that I don't want to auto increment (for various reasons) and so I'm looking for a way to simply increment that field when I INSERT. By simply, I mean without stored procedures and without triggers, so just a series of SQL commands (preferably one command).
Here is what I have tried thus far:
BEGIN TRAN
INSERT INTO Table1(id, data_field)
VALUES ( (SELECT (MAX(id) + 1) FROM Table1), '[blob of data]');
COMMIT TRAN;
* Data abstracted to use generic names and identifiers
However, when executed, the command errors, saying that
"Subqueries are not allowed in this
context. only scalar expressions are
allowed"
So, how can I do this/what am I doing wrong?
EDIT: Since it was pointed out as a consideration, the table to be inserted into is guaranteed to have at least 1 row already.
You understand that you will have collisions right?
you need to do something like this and this might cause deadlocks so be very sure what you are trying to accomplish here
DECLARE #id int
BEGIN TRAN
SELECT #id = MAX(id) + 1 FROM Table1 WITH (UPDLOCK, HOLDLOCK)
INSERT INTO Table1(id, data_field)
VALUES (#id ,'[blob of data]')
COMMIT TRAN
To explain the collision thing, I have provided some code
first create this table and insert one row
CREATE TABLE Table1(id int primary key not null, data_field char(100))
GO
Insert Table1 values(1,'[blob of data]')
Go
Now open up two query windows and run this at the same time
declare #i int
set #i =1
while #i < 10000
begin
BEGIN TRAN
INSERT INTO Table1(id, data_field)
SELECT MAX(id) + 1, '[blob of data]' FROM Table1
COMMIT TRAN;
set #i =#i + 1
end
You will see a bunch of these
Server: Msg 2627, Level 14, State 1, Line 7
Violation of PRIMARY KEY constraint 'PK__Table1__3213E83F2962141D'. Cannot insert duplicate key in object 'dbo.Table1'.
The statement has been terminated.
Try this instead:
INSERT INTO Table1 (id, data_field)
SELECT id, '[blob of data]' FROM (SELECT MAX(id) + 1 as id FROM Table1) tbl
I wouldn't recommend doing it that way for any number of reasons though (performance, transaction safety, etc)
It could be because there are no records so the sub query is returning NULL...try
INSERT INTO tblTest(RecordID, Text)
VALUES ((SELECT ISNULL(MAX(RecordID), 0) + 1 FROM tblTest), 'asdf')
I don't know if somebody is still looking for an answer but here is a solution that seems to work:
-- Preparation: execute only once
CREATE TABLE Test (Value int)
CREATE TABLE Lock (LockID uniqueidentifier)
INSERT INTO Lock SELECT NEWID()
-- Real insert
BEGIN TRAN LockTran
-- Lock an object to block simultaneous calls.
UPDATE Lock WITH(TABLOCK)
SET LockID = LockID
INSERT INTO Test
SELECT ISNULL(MAX(T.Value), 0) + 1
FROM Test T
COMMIT TRAN LockTran
We have a similar situation where we needed to increment and could not have gaps in the numbers. (If you use an identity value and a transaction is rolled back, that number will not be inserted and you will have gaps because the identity value does not roll back.)
We created a separate table for last number used and seeded it with 0.
Our insert takes a few steps.
--increment the number
Update dbo.NumberTable
set number = number + 1
--find out what the incremented number is
select #number = number
from dbo.NumberTable
--use the number
insert into dbo.MyTable using the #number
commit or rollback
This causes simultaneous transactions to process in a single line as each concurrent transaction will wait because the NumberTable is locked. As soon as the waiting transaction gets the lock, it increments the current value and locks it from others. That current value is the last number used and if a transaction is rolled back, the NumberTable update is also rolled back so there are no gaps.
Hope that helps.
Another way to cause single file execution is to use a SQL application lock. We have used that approach for longer running processes like synchronizing data between systems so only one synchronizing process can run at a time.
If you're doing it in a trigger, you could make sure it's an "INSTEAD OF" trigger and do it in a couple of statements:
DECLARE #next INT
SET #next = (SELECT (MAX(id) + 1) FROM Table1)
INSERT INTO Table1
VALUES (#next, inserted.datablob)
The only thing you'd have to be careful about is concurrency - if two rows are inserted at the same time, they could attempt to use the same value for #next, causing a conflict.
Does this accomplish what you want?
It seems very odd to do this sort of thing w/o an IDENTITY (auto-increment) column, making me question the architecture itself. I mean, seriously, this is the perfect situation for an IDENTITY column. It might help us answer your question if you'd explain the reasoning behind this decision. =)
Having said that, some options are:
using an INSTEAD OF trigger for this purpose. So, you'd do your INSERT (the INSERT statement would not need to pass in an ID). The trigger code would handle inserting the appropriate ID. You'd need to use the WITH (UPDLOCK, HOLDLOCK) syntax used by another answerer to hold the lock for the duration of the trigger (which is implicitly wrapped in a transaction) & to elevate the lock type from "shared" to "update" lock (IIRC).
you can use the idea above, but have a table whose purpose is to store the last, max value inserted into the table. So, once the table is set up, you would no longer have to do a SELECT MAX(ID) every time. You'd simply increment the value in the table. This is safe provided that you use appropriate locking (as discussed). Again, that avoids repeated table scans every time you INSERT.
use GUIDs instead of IDs. It's much easier to merge tables across databases, since the GUIDs will always be unique (whereas records across databases will have conflicting integer IDs). To avoid page splitting, sequential GUIDs can be used. This is only beneficial if you might need to do database merging.
Use a stored proc in lieu of the trigger approach (since triggers are to be avoided, for some reason). You'd still have the locking issue (and the performance problems that can arise). But sprocs are preferred over dynamic SQL (in the context of applications), and are often much more performant.
Sorry about rambling. Hope that helps.
How about creating a separate table to maintain the counter? It has better performance than MAX(id), as it will be O(1). MAX(id) is at best O(lgn) depending on the implementation.
And then when you need to insert, simply lock the counter table for reading the counter and increment the counter. Then you can release the lock and insert to your table with the incremented counter value.
Have a separate table where you keep your latest ID and for every transaction get a new one.
It may be a bit slower but it should work.
DECLARE #NEWID INT
BEGIN TRAN
UPDATE TABLE SET ID=ID+1
SELECT #NEWID=ID FROM TABLE
COMMIT TRAN
PRINT #NEWID -- Do what you want with your new ID
Code without any transaction scope (I use it in my engineer course as an exercice) :
-- Preparation: execute only once
CREATE TABLE increment (val int);
INSERT INTO increment VALUES (1);
-- Real insert
DECLARE #newIncrement INT;
UPDATE increment
SET #newIncrement = val,
val = val + 1;
INSERT INTO Table1 (id, data_field)
SELECT #newIncrement, 'some data';
declare #nextId int
set #nextId = (select MAX(id)+1 from Table1)
insert into Table1(id, data_field) values (#nextId, '[blob of data]')
commit;
But perhaps a better approach would be using a scalar function getNextId('table1')
Any critiques of this? Works for me.
DECLARE #m_NewRequestID INT
, #m_IsError BIT = 1
, #m_CatchEndless INT = 0
WHILE #m_IsError = 1
BEGIN TRY
SELECT #m_NewRequestID = (SELECT ISNULL(MAX(RequestID), 0) + 1 FROM Requests)
INSERT INTO Requests ( RequestID
, RequestName
, Customer
, Comment
, CreatedFromApplication)
SELECT RequestID = #m_NewRequestID
, RequestName = dbo.ufGetNextAvailableRequestName(PatternName)
, Customer = #Customer
, Comment = [Description]
, CreatedFromApplication = #CreatedFromApplication
FROM RequestPatterns
WHERE PatternID = #PatternID
SET #m_IsError = 0
END TRY
BEGIN CATCH
SET #m_IsError = 1
SET #m_CatchEndless = #m_CatchEndless + 1
IF #m_CatchEndless > 1000
THROW 51000, '[upCreateRequestFromPattern]: Unable to get new RequestID', 1
END CATCH
This should work:
INSERT INTO Table1 (id, data_field)
SELECT (SELECT (MAX(id) + 1) FROM Table1), '[blob of data]';
Or this (substitute LIMIT for other platforms):
INSERT INTO Table1 (id, data_field)
SELECT TOP 1
MAX(id) + 1, '[blob of data]'
FROM
Table1
ORDER BY
[id] DESC;