how to
compare the values of same table(say for eg: Order table) each and every time the record get inserted ,
if the record with same values get inserted already in same table i should not insert the new record with same values. how to do that exactly in sql server 2008
If exists(select * from Order where key_column=#some_value)
print 'data already exists'
else
Insert into Order(columns) values (#some_value,...)
I'd suggest adding a unique index on the key columns...
ALTER TABLE mytable ADD UNIQUE INDEX myindex (keycolumn1, keycolumn2, ...);
That'd make it impossible to insert a duplicate by accident.
Related
In my SQL Server table, I have a table whose PK is GUID with lots of records already.
Now I want to add records which only needs to change the COMMON_ID and COMMON_ASSET_TYPE column of some existing records.
select * from My_Table where COMMON_ASSET_TYPE = "ASSET"
I am writing sql to copy above query result, changing COMMON_ID value to new GUID value and COMMON_ASSET_TYPE value from "ASSET" to "USER", then insert the new result into My_Table.
I do not know how to write it since now I feel it is a trouble to insert records manually.
Update:
I have far more columns in table and most of them are not nullable, I want to keep all these columns' data for new records except above two columns.Is there any way if I do not have to write all these column names in sql?
Try to use NEWID if you want to create new guid:
INSERT INTO dbo.YourTable
(
COMMON_ID,
COMMON_ASSET_TYPE
)
select NEWID(), 'User' as Common_Asset_Type
from My_Table
where COMMON_ASSET_TYPE = "ASSET"
UPDATE:
As a good practice I would suggest to write all column names explicitly to have a clean and clear insert statement. However, you can use the following construction, but it is not advisable in my opinion:
insert into table_One
select
id
, isnull(name,'Jon')
from table_Two
INSERT INTO My_Table (COMMON_ID,COMMON_LIMIT_IDENTITY, COMMON_CLASS_ID,COMMON_ASSET_TYPE)
SELECT NEWID(), COMMON_LIMIT_IDENTITY, COMMON_CLASS_ID,'USER'
FROM My_Table
WHERE COMMON_ASSET_TYPE = 'ASSET'
If I've understood correctly you want to take existing records in your table, modify them, and insert them as new records in the same table.
I'll assume ID column contains the the GUID?
I'd first create a temporary table
CREATE TABLE #myTempTable(
ID UNIQUEIDENTIFIER,
Name varchar(max),
... etc
);
Fill this temp table with the records to change with your SELECT statement.
Change the records in the temp table using UPDATE statement.
Finally, Insert those "new" records back into the primary table. with INSERT INTO SELECT statement.
You will probably have to sandwitch the INSERT INTO SELECT with IDENTITY_INSERT (on/off):
SET IDENTITY_INSERT schema_name.table_name ON
SET IDENTITY_INSERT schema_name.table_name OFF
IDENTITY_INSERT "Allows explicit values to be inserted into the identity column of a table."
I am using Access 2013 and I am trying to insert rows to a table but I don't want any duplicates. Basically if not exists in table enter the data to table. I have tried to using 'Not Exists' and 'Not in' and currently it still does not insert to table. Here is my code if I remove the where condition then it inserts to table but If I enter same record it duplicates. Here is my code:
INSERT INTO [UB-04s] ( consumer_id, prov_id, total_charges, [non-covered_chrgs], patient_name )
VALUES ([Forms]![frmHospitalEOR]![client_ID], [Forms]![frmHospitalEOR]![ID], Forms![frmHospitalEOR].[frmItemizedStmtTotals].Form.[TOTAL BILLED], Forms![frmHospitalEOR].[frmItemizedStmtTotals].Form.[TOTAL BILLED], [Forms]![frmHospitalEOR]![patient_name])
WHERE [Forms]![frmHospitalEOR]![ID]
NOT IN (SELECT DISTINCT prov_id FROM [UB-04s]);
You cannot use WHERE in this kind of SQL:
INSERT INTO tablename (fieldname) VALUES ('value');
You can add a constraint to the database, like a unique index, then the insert will fail with an error message. It is possible to have multiple NULL values for several rows, the unique index makes sure that rows with values are unique.
To avoid these kind of error messages you can build a procedure or use code to check data first, and then perform some action - like do the insert or cancel.
This select could be used to check data:
SELECT COUNT(*) FROM [UB-04s] WHERE prov_id = [Forms]![frmHospitalEOR]![ID]
It will return number of rows with the spesific value, if it is 0 then you are redy to run the insert.
I have a set of value which have to be inserted into two tables.Input has say 5 row and I have to insert these 5 rows into table A first.Table A has a identity column.Next i have to insert these 5 rows into table B with an extra column which is the identity from table A.
How this can be done with out using any loops?
Any help will be highly helpful.
INSERT INTO TABLE_A(COL2,COL3)
SELECT COL2,COL3 FROM #TEMP_TAB
set #identityval=##identity
INSERT INTO TABLE_B(COLA,COLB,COLC)
SELECT #identityval,COL2,COL3,COL4 FROM #TEMP_TAB
You cannot insert into multiple tables using a single statment.
What you could do is create an insert trigger on Table A so that after the insert occurs this performs the new insert with the identity of the value inserted into Table A and insert it into Table B.
Here is one solution.
take max of identity column from table TABLE_A
insert new records in table TABLE_A
then insert records on TABLE_B from TABLE_A with Identity greater than last max identity.
Thanks,
Gopal
What you want to do is not possible.
You can get only the value from the last insert using the ##identity variable. This way its possible to add to multiple tables setting the right foreign key without selecting the just inserted row again using a cursor. This approach is not useful when inserting multiple rows at once.
From the documentation:
Use the ##identity global variable to retrieve the last value inserted into an IDENTITY column. The value of ##identity changes each time an insert or select into attempts to insert a row into a table.
Here is a procedure which inserts a single row and you can use the return value to create a reference to the inserted data in another table:
create procedure reset_id as
set identity_insert sales_daily on
insert into sales_daily (syb_identity, stor_id)
values (102, "1349")
select ##identity
select ##identity
execute reset_id
In SQL server, I'm using a table variable and when done manipulating it I want to insert its values into a real table that has an identity column which is also the PK.
The table variable I'm making has two columns; the physical table has four, the first of which is the identity column, an integer IK. The data types for the columns I want to insert are the same as the target columns' data types.
INSERT INTO [dbo].[Message] ([Name], [Type])
SELECT DISTINCT [Code],[MessageType]
FROM #TempTableVariable
This fails with:
Cannot insert duplicate key row in object 'dbo.Message' with unique index
'IX_Message_Id'. The duplicate key value is (ApplicationSelection).
But when trying to insert just Values (...) it works ok.
How do I get it right?
It appears that the data "ApplicationSelection" is already in the database. YOu need to write the select to exclude records that are already in the database. YOu can do that with a where not exists clause or a left join. LOok up teh index to see what field is unique besides the identity. That will tell you what feild you need to check to see if teh record currently exists.
Sybase db tables do not have a concept of self updating row numbers. However , for one of the modules , I require the presence of rownumber corresponding to each row in the database such that max(Column) would always tell me the number of rows in the table.
I thought I'll introduce an int column and keep updating this column to keep track of the row number. However I'm having problems in updating this column in case of deletes. What sql should I use in delete trigger to update this column?
You can easily assign a unique number to each row by using an identity column. The identity can be a numeric or an integer (in ASE12+).
This will almost do what you require. There are certain circumstances in which you will get a gap in the identity sequence. (These are called "identity gaps", the best discussion on them is here). Also deletes will cause gaps in the sequence as you've identified.
Why do you need to use max(col) to get the number of rows in the table, when you could just use count(*)? If you're trying to get the last row from the table, then you can do
select * from table where column = (select max(column) from table).
Regarding the delete trigger to update a manually managed column, I think this would be a potential source of deadlocks, and many performance issues. Imagine you have 1 million rows in your table, and you delete row 1, that's 999999 rows you now have to update to subtract 1 from the id.
Delete trigger
CREATE TRIGGER tigger ON myTable FOR DELETE
AS
update myTable
set id = id - (select count(*) from deleted d where d.id < t.id)
from myTable t
To avoid locking problems
You could add an extra table (which joins to your primary table) like this:
CREATE TABLE rowCounter
(id int, -- foreign key to main table
rownum int)
... and use the rownum field from this table.
If you put the delete trigger on this table then you would hugely reduce the potential for locking problems.
Approximate solution?
Does the table need to keep its rownumbers up to date all the time?
If not, you could have a job which runs every minute or so, which checks for gaps in the rownum, and does an update.
Question: do the rownumbers have to reflect the order in which rows were inserted?
If not, you could do far fewer updates, but only updating the most recent rows, "moving" them into gaps.
Leave a comment if you would like me to post any SQL for these ideas.
I'm not sure why you would want to do this. You could experiment with using temporary tables and "select into" with an Identity column like below.
create table test
(
col1 int,
col2 varchar(3)
)
insert into test values (100, "abc")
insert into test values (111, "def")
insert into test values (222, "ghi")
insert into test values (300, "jkl")
insert into test values (400, "mno")
select rank = identity(10), col1 into #t1 from Test
select * from #t1
delete from test where col2="ghi"
select rank = identity(10), col1 into #t2 from Test
select * from #t2
drop table test
drop table #t1
drop table #t2
This would give you a dynamic id (of sorts)