I'm attempting to use SSIS to do a data migration from an old system to a new system. I have the tables TableA, TableB and OldTable. The tables are as follows:
TableA
ID
BusinessTypeEnum
Other
TableB
ID
TableB_ID (FK)
PermitNumber
OldTable
ID
BusinessType
PermitNumber
As you can see, TableA and TableB (which are in the new system) are really OldTable separated out into two tables.
My problem is that in order to insert a record in TableB I need to know that PrimaryKey that was assigned at the time the corresponding records was inserted in TableA.
I had originally planned on doing a LookUp when attempting to insert records into table TableB however, there isn't any data stored in TableA that would allow me to return.
Any ideas?
It sounds like you're using a single data flow: source -> split -> two destinations (TableA, TableB).
What if you divided the process into two data flows?
The first simply pulls from OldTable and loads into TableA.
The second--loading into TableB--again pulls from OldTable but also gets the relevant identity value from TableA by doing a Merge Join to, or a Lookup from, that table.
(Note: the second flow needs to be set to run only after the first completes via a precedence constraint as it relies on OldTable's data being inserted into TableA before its run.)
You can use the OUTPUT Clause in our insert statement to return the value of the identity column.
INSERT TableA (BusinessTypeEnum, Other)
OUTPUT INSERTED.ID
VALUES ('abc', 'def')
in addition to inserting a record, the above will act like a select.
I should mention that there is an INTO clause in the OUTPUT clause that can be used with a batch insert. The above example is for a single record insert.
Related
I have two tables with the same field names and a stored procedure that updates table B with Table A's data by doing a delete from current table and insert into current table from another table that has update values in it:
delete from ac.Table1
insert into ac.Table1
select *
from dbo.OriginalTable
where dtcreate <getdate()-1
I had to recreate Table1 through GIS software which adds GlobalIDs and an Object ID field. The original order had Object ID at the end and the new table has it at the front. Will this impact executing the SQL statement above?
Yes it will. The order of the columns should match for each value to go in desired column
You can try
Insert into ac.Table1 (column1....columnN)
I have Table A and Table B.
Table A contains data from another source.
Table B contains data that is inserted from Table A along with data from other tables. I have done the initial insert of data from A to B but now what I am trying to do is insert the records that do not exist already in Table B from Table A on a daily basis. Unfortunately, there is no primary key or unique identifier in Table A which is making this difficult.
Table A contains a field called file_name which has values that looks like this:
this_is_a_file_name_01011980.txt
There can be duplicate values in this column (multiple files from the same date).
In Table B I created a column data_date which extracts the date from the table a.file_name field. There is also a load_date field which just uses GETDATE() at the time the data is inserted.
I am thinking I can somehow compare the dates in these tables to decide what needs to be inserted. For example:
If the file date from Table A (would need to extract again) is greater than the load_date of Table B, then insert these records into Table B.
Let me know if any clarification is needed.
You could use exists or except. With the explanation here it seems like except would make short work of this. Something like this.
insert tableB
select * from tableA
except
select * from tableB
I need to insert a row into a table if a particular row in another table is updated.
How do I do an IF statement in the the DB trigger on Table1, saying if Table1.column1 = 'TC' then INSERT a row in Table2.
You would do this in an update trigger on the 'other' table.
There are two special tables in triggers: inserted and deleted. You join these two tables in such a way that the result set is the rows you wish to insert. Ergo -
create trigger [after_update_on_Table1] on [Table1] for update
as
...
insert
into [Table2] (...)
select
...
from
inserted as i
inner join
deleted as d
on (i.<*pk*> = d.<*pk*>)
where
<*other conditions if applicable*>
...
<pk> is whatever the appropriate primary key would be. If this is a compound primary key then AND together the different primary key components.
For what you describe thus far you do not require an if statement.
What is the purpose of the OUTPUT clause? I have gone through the MSDN documentation for the OUTPUT clause, which includes the following example:
DELETE FROM dbo.table1
OUTPUT DELETED.* INTO #MyTableVar
WHERE id = 4 OR id = 2;
From the above query, it seems that deleted records are saved in some magic table called deleted, and the query will load those records into table called MyTableVar from the magic deleted table. .
I still do not understand the purpose of the OUTPUT clause usage.
As another SQL example:
USE AdventureWorks2012;
GO
DECLARE #MyTableVar table( NewScrapReasonID smallint,
Name varchar(50),
ModifiedDate datetime);
INSERT Production.ScrapReason
OUTPUT INSERTED.ScrapReasonID, INSERTED.Name, INSERTED.ModifiedDate
INTO #MyTableVar
VALUES (N'Operator error', GETDATE());
--Display the result set of the table variable.
SELECT NewScrapReasonID, Name, ModifiedDate FROM #MyTableVar;
--Display the result set of the table.
SELECT ScrapReasonID, Name, ModifiedDate
FROM Production.ScrapReason;
GO
What is this actually doing? Can anyone explain what this clause is doing with an easy example?
UPDATE with non-functioning example:
create proc test
as
CREATE TABLE dbo.table1
(
id INT,
employee VARCHAR(32)
)
go
INSERT INTO dbo.table1 VALUES
(1, 'Fred')
,(2, 'Tom')
,(3, 'Sally')
,(4, 'Alice')
delete from table1
select * from deleted
This gives me an error when I run it, because it can't see the deleted table.
The general purpose of this clause is to capture the changes made to your data without an additional query, which would introduce locking and blocking issues. Example:
DELETE FROM X WHERE Name = 'Foo'
You want to know which IDs were deleted. You can do this naively like this:
SELECT ID FROM X WHERE Name = 'Foo'
DELETE FROM X WHERE Name = 'Foo'
But these selected IDs are unreliable unless you are running in a transaction with isolation level SERIALIZABLE which is usually not the case. Someone else can add, delete or change "Foo"-Records between your two statements. So instead you can use the OUTPUT clause and get back exactly and reliably the deleted IDs without any performance or reliability issues.
Another frequent use is to get the value of inserted default values, especially when using identity columns. For a single insert you can do this:
CREATE TABLE X
(
ID INT IDENTITY,
Name VARCHAR(10)
);
INSERT X (Name) VALUES ('Foo')
SELECT SCOPE_IDENTITY()
But SCOPE_IDENTITY() can give you only the last inserted ID. If you do multiple inserts, like
INSERT X (Name) VALUES ('Foo'), ('Bar')
or
INSERT X (Name) SELECT OtherName FROM Y
and you want to know the inserted IDs, you are out of luck. You can try to find them with another SELECT, but you need another unique column to even formulate the query and then you run into the same issues as with the DELETE sample above. So, the OUTPUT clause lets you identify neatly which Names got which IDs.
You will need these IDs for example when creating dependent records with foreign keys. Think "Order" and "OrderDetails" which are linked by an OrderID column with an IDENTITY clause. Again, with a single INSERT you can get away with using SCOPE_IDENTITY() or ##IDENTITY, but when inserting multiple orders at once, you will need OUTPUT.
When you perform Insert/Update/Delete operation on particular table and want to know what rows are affected OR want to log them for audit trail OR you want to use multiple values of affected rows in subsequent sql statements, you can use OUTPUT clause.
For Insert statement, it will have INSERTED table.
For Delete statement, it will have DELETED table. In case of Update DELETED table will contain rows (with old values) before update operation performed.
For Update statement, it will have DELETED and INSERTED tables.
DELETED table will contain rows (with old values) before update operation performed.
INSERTED table will contain rows (with new values) after update operation performed.
USE AdventureWorks2012;
GO
DECLARE #MyTableVar table( NewScrapReasonID smallint,
Name varchar(50),
ModifiedDate datetime);
INSERT Production.ScrapReason
OUTPUT INSERTED.ScrapReasonID, INSERTED.Name, INSERTED.ModifiedDate
INTO #MyTableVar
VALUES (N'Operator error', GETDATE());
--Display the result set of the table variable.
SELECT NewScrapReasonID, Name, ModifiedDate FROM #MyTableVar;
--Display the result set of the table.
SELECT ScrapReasonID, Name, ModifiedDate
FROM Production.ScrapReason;
Now your query inserts rows in Production.ScrapReason as well as table variable #MyTableVar. Later it selects inserted rows from Production.ScrapReason and #MyTableVar. Thus you can compare both the resultset and it must have identical rows (considering Production.ScrapReason is empty table.)
I hope it makes sense!
Edit:
Inserted/Deleted tables will be available with Insert/Update/Delete statement and not after that. You may want to store those magic table values in db table or temp table.
Without the OUTPUT clause, how would you know which rows were deleted? Your example seems so simple because you already know the Id values, but what if you did this:
DELETE FROM T WHERE SomeColumn LIKE 'SomePattern%'
And you want to find out what was deleted. That's the purpose of the OUTPUT clause.
I'm not sure if this is well designed, if it's not please, advice me on how to do this.
I'm using Sql Server 2008
I have:
TableA (TableA_ID int identity PK, Value varchar(10), TableB_ID PK not null)
TableB (TableB_ID int identity PK, Value varchar(10), TableA_ID PK not null)
The goal is simple:
TableA can have rows only if there is at least 1 row in TableB associated with TableA;
And for each row in TableB, there must be a row associated with it in TableA);
TableA is the "Parent Table", and TableB is the "Children's table", it's something like, a parent should have 1 or more children, and each child can have only 1 parent.
Is this right?
The problem I'm having is when I try to do an INSERT statement, if this is correct, how should I make the INSERT? temporary disable the constraints?
Thanks!
The problem I'm having is when I try to insert
TableA (TableA_ID int identity PK, Value varchar(10))
TableB (TableB_ID int identity PK, Value varchar(10), TableA_ID not null)
as a parent, table a does not need to reference table b, since table be requires there be a field in table a. this is called a one to many relationship.
so in table a you might have these values:
1 a
2 b
3 c
and in table b you could have these:
1 asdf 1
2 sdfg 1
3 pof 2
4 dfgbsd 3
now you can make a query to show the data from table a with this:
select b.TableB_ID, b.Value, a.TableA_ID, a.Value
from TableB b
inner join TableA
on b.TableA_ID=a.TableA_ID
The parents don't depend on the children. You need to remove your reference to Table B in Table A.
You have a circular dependency. These don't really work well for declarative enforcement, you would have to disable the constraints every time you wanted to insert.
That's an unusual requirement. If I was stuck with it (and I would really push back to make sure it was indeed a requirement) I would design it this way:
Make a regular foreign key from table a to table b with a the parent and b the child.
Add a trigger to table a that inserts a record to table b if one does not exist when a table a record is inserted. Add another trigger to table b that deletes the table a record if the last related record in table b is deleted.
ALternatively, you could put the inserts to both tables ina stored proc. Remove all insert rights to the table except through the proc. YOu would still need the foreign key relationship from tablea to table b and the trigger on table b to ensure that if the last record is deleted the table a record is deleted. But you could do away with the trigger on table a in this case.
I would use the first scenario unless there is information in table b that cannot be found from the trigger on table a, say one or more required fields that don't have a value you can figur eout form table a.
I would put the inserts into a proc: disable the constraints, insert the data, enable the constraints. You may need to make sure that this is the only transaction going on whilst the constraints are disabled though.
That could be acheived by making the isolation level SERIALIZABLE, but that in turn could massace your concurrency.
Kev