Hi need insert data in table if the record is not already exits
Ex:
IF NOT EXISTS (SELECT Id FROM table WHERE id=_Id) THEN
INSERT INTO tbale(.....)
This can be easily done using stored procedure in MySql. But I want to d same thing in SQLite by writing a single query statement.
Pleas help
INSERT INTO CategoryMaster (CategoryID, CategoryText) SELECT %d,'%#' WHERE NOT EXISTS (SELECT 1 FROM CategoryMaster WHERE CategoryID= %d)
Its working for me :)
SQlite doesn't have stored procedudes that you need to do logic like this. But you can always extend sqlite with simple C-functions. Or you could simply code this logic in whatever language you are writing your program in. I don't think the performance hit is that great. Did your profiling show that this is a critical path that needs to be optimized?
Put a unique index on the id column (or make it the primary key) then use:
REPLACE INTO table(.....)
see:
http://www.sqlite.org/lang_insert.html or http://www.sqlite.org/lang_replace.html
I would do this by running a first query to see if the record exists then decide whether to run an insert or update. I don't think SQLite has a fully featured query language to support the desired shorter approach.
Related
In a stored procedure (using SQL Server 2008 R2 SP2) is it possible to return a NewSequentialID() without a temp table variable?
I can successfully obtain the NewSequentialID() by using a temp table:
Getting Value of NEWSEQUENTIALID() on Insert
Perhaps I’m old school, but I try to refrain from using temp tables unless absolutely necessary… though this might be a case where it is absolutely necessary…
IF I try:
DECLARE #NewSequentialID UNIQUEIDENTIFIER;
SET #NewSequentialID = NEWID()
… it works as expected.
IF I try:
DECLARE #NewSequentialID UNIQUEIDENTIFIER;
SET #NewSequentialID = NEWSEQUENTIALID()
… I receive the following error:
The newsequentialid() built-in function can only be used in a DEFAULT
expression for a column of type ‘uniqueidentifier’ in a CREATE TABLE
or ALTER TABLE statement. It cannot be combined with other operators
to form a complex scalar expression.
Is the ONLY solution to use a temp table method?
Does anyone know of a reason why Microsoft implemented a difference between NEWSEQUENTIALID() to work like NEWID()?
Anyone know if there's a chance Microsoft will update NEWSEQUENTIALID() to work like NEWID()?
Geo
UPDATE --
I'm not sure why Microsoft choose to implement the method in this manner, since they state that, "NEWSEQUENTIALID is a wrapper over the Windows UuidCreateSequential function"... but it appears that there is no non-temp-variable table method. (At least as of yet.)Thanks for everyone's comments / answers. [Moderator Note:] I'm not sure what to do with a question when the answer is "not possible". So I'm going to give #marc_s credit for detailing a workaround.
For now - newsequentialid() can only be used as a default constraint on a column. That's what the error message pretty clearly says, too.
So in order to get your sequential GUID's - you must have a table. No other way to do this. And no other way in SQL Server 2012, either.
I have no idea nor any information as to why there's such a difference, and why Microsoft chose to implement it this way....
Update:
OK, so you need to get that value that is being inserted into your table - how about using the OUTPUT clause?
Something like:
DECLARE #NewIDs TABLE (NewSeqID UNIQUEIDENTIFIER)
INSERT INTO dbo.YourTable(list-of-columns)
OUTPUT INSERTED.NewSeqID INTO #NewIDs(NewSeqID)
VALUES (.........)
This way, the output from the INSERT operation - the newly created sequential GUIDs - is being stored into that table variable, and you can use that, return it, slice it - whatever you like!
the official Microsoft saying is:
NEWSEQUENTIALID() can only be used with DEFAULT constraints on table
columns of type uniqueidentifier. For example: CREATE TABLE myTable
(ColumnA uniqueidentifier DEFAULT NEWSEQUENTIALID())
described here
http://msdn.microsoft.com/en-us/library/ms189786.aspx
NewID generates a random number and the other is the next sequential number.
I am have two fields in my table:
One is Primary key auto increment value and second is text value.
lets say: xyzId & xyz
So I can easily insert like this
insert into abcTable(xyz) Values('34')
After performing above query it must insert these information
xyzId=1 & xyz=34
and for retrieving I can retrieve like this
select xyzId from abcTable
But for this I have to write down two operation. Cant I retrieve in single/sub query ?
Thanks
If you are on SQL Server 2005 or later you can use the output clause to return the auto created id.
Try this:
insert into abcTable(xyz)
output inserted.xyzId
values('34')
I think you can't do an insert and a select in a single query.
You can use a Store Procedures to execute the two instructions as an atomic operation or you can build a query in code with the 2 instructions using ';' (semicolon) as a separator betwen instructions.
Anyway, for select identity values in SQL Server you must check ##IDENTITY, SCOPE_IDENTITY and IDENT_CURRENT. It's faster and cleaner than a select in the table.
INSERT INTO contacts_lists (contact_id, list_id)
SELECT contact_id, 67544
FROM plain_contacts
Here I want to use Copy command instead of Insert command in sql to reduce the time to insert values. I fetched the data using select operation. How can i insert it into a table using Copy command in postgresql. Could you please give an example for it?. Or any other suggestion in order to achieve the reduction of time to insert the values.
As your rows are already in the database (because you apparently can SELECT them), then using COPY will not increase the speed in any way.
To be able to use COPY you have to first write the values into a text file, which is then read into the database. But if you can SELECT them, writing to a textfile is a completely unnecessary step and will slow down your insert, not increase its speed
Your statement is as fast as it gets. The only thing that might speed it up (apart from buying a faster harddisk) is to remove any potential index on contact_lists that contains the column contact_id or list_id and re-create the index once the insert is finished.
You can find the syntax described in many places, I'm sure. One of those is this wiki article.
It looks like it would basically be:
COPY plain_contacts (contact_id, 67544) TO some_file
And
COPY contacts_lists (contact_id, list_id) FROM some_file
But I'm just reading from the resources that Google turned up. Give it a try and post back if you need help with a specific problem.
I have a stored procedure which creates and works with a temporary #table
Some of the queries would be tremendously optimized if that temporary #table would have an index created on it.
However, creating an index within the stored procedure fails:
create procedure test1 as
SELECT f1, f2, f3
INTO #table1
FROM main_table
WHERE 1 = 2
-- insert rows into #table1
create index my_idx on #table1 (f1)
SELECT f1, f2, f3 FROM #table1 (index my_idx) WHERE f1 = 11 -- "QUERY X"
When I call the above, the query plan for "QUERY X" shows a table scan.
If I simply run the code above outside the stored procedure, the messages show the following warning:
Index 'my_idx' specified as optimizer hint in the FROM clause of table '#table1' does not exist. Optimizer will choose another index instead.
This can be resolved when running ad-hoc (outside the stored procedure) by splitting the code above in two batches by addding "go" after index creation:
create index my_idx on #table1 (f1)
go
Now, "QUERY X" query plan shows the use of index "my_idx".
QUESTION: How do I mimique running the "create index" in a separate batch when it's inside the stored procedure? I can't insert a "go" there like I do with the ad-hoc copy above. Please note that I'm aware of the solution of "split up the 'QUERY X' into a separate stored procedure" and am looking for a solution that will avoid that.
P.S. If it matters, this is on Sybase 12 (ASE 12.5.4)
UPDATE:
I have been seeing several references to "schema bumping" during my Googling before posing the question. But that doesn't seem to happen in my case.
You can create a table, populate it, create an index on it and select values
from it in the same porc and have the optimizer fully cost it based on
accurate information. This is called 'schema bumping' and has been in place
since 11.5.1.
The Sybase documentation says that you create and use a temporary index in the same stored procedure:
http://infocenter.sybase.com/help/index.jsp?topic=/com.sybase.dc20023_1251/html/optimizer/X26029.htm
I think to get around this you will need to split your stored procedure into at least two parts, one to create and populate the table then build the index, and then a second one to run the select query.
I am not sure how you are getting this problem, might be in older version of Sybase, however with version 12.5.4 I tried executing the same thing as suggested by you but in my case the optimizer correctly suggested the use of index created in the stored procedure. Usually in a stored procedure we do not need to break sql into batches because else we would have been required to have a seperate batch for create table command as well.
In case we try to create index within a same batch (not in a stored procedure) we will do get the same error as specified by you above because we are trying to create an index on a table and then trying to use it within the same batch. Usually the Sybase server will compile the whole batch in one go and hence the problem. But as far as stored procedure is concerned in Sybase 12.5.4 there will be no problem.
In a similar vein to my previous question I again ask the SO guys for your collective wisdom and help.
In a stored procedure and after passing some checks I need to insert a new row and return the newly created id for it. The check if a row exists works so it is the bit after that which I am undecided upon.
The table has two important columns: The LocationID and the CaseID. The CaseID is autoincrementing, so when you add insert a new locationid it will automatically rachet up.
I currently have this:
-- previous checks for existance of CaseID
IF #CaseID IS NULL
BEGIN
INSERT INTO
Cases(LocationID)
VALUES
(#LocationID)
-- what now?
END
I was thinking of performing a #CaseID = (SELECT blah) statement immeadiately after but I was wondering if there is a better way?
Is there a better way? How would you do this?
SELECT #CaseID = SCOPE_IDENTITY()
In fact, you can just do (if that's the end of the stored proc.):
SELECT SCOPE_IDENTITY()
(The OUTPUT clause is only available in SQL Server 2005 onwards...)
Ref: SCOPE_IDENTITY
scope_identity()
SELECT SCOPE_IDENTITY()
As others mentioned, SCOPE_IDENTITY() is the way to go, though some ORM tools provide this functionality as well.
The only thing you need to remember is SCOPE_IDENTITY() will return the last identity key value generated during the current session only. This is useful in filtering out new keys which may have been created by other clients simultaneously. SELECT ##IDENTITY will return the last key generated by any client/session.
You need to use the OUTPUT clause
http://blog.jemm.net/articles/databases/how-to-using-sql-server-2005s-output-to-return-generated-identity/
...which, as pointed out, is only available in sqlserver 2005. Plz disregard.