I tried to configure the lookup to only send no match output (Only want records that haven't been written to destination), but the same amount of records get written over and over. Is there something I am missing? I have the fields the lookup needs to match on, so if no match I want it to write to new location.
Specify how to handle rows with no matching entries is set to Redirect rows to no match output.
I would normally just use a query but where I am at the source and the destination are on two different servers.
With that Lookup configuration, you will have 2 green output paths available from the Lookup object. One will be the Lookup Match Output and the other will be the Lookup No Match Output.
When connecting the Lookup to your downstream transformations, you need to carefully select which output path goes where. The one you probably want is the Lookup No Match Output.
Related
I have a huge SQL query with multiple sub-tables (sub-table output is not retained) that is generating a final output in a specific format (format is fixed as it is expected by another service). I want to also generate some counts of the sub-tables in the query. A simple solution would be to re-write and run the query again, and get the counts.
However, I want to avoid double executions/computations of the same things and don't want to store the sub-tables either. I want to be able to either append these counts to the data output (will need to modify the service to ignore these count values accordingly) OR be able to write these counts to another location.
I'm using 'unload to S3' command (https://docs.aws.amazon.com/redshift/latest/dg/t_Unloading_tables.html), where all the results are stored in a S3 location.
Is it possible to achieve this? If so, how?
In my current SSIS data flow task, I feed my data flow into a Lookup tool. Matches are inserted into one table and non-matches are inserted into another table.
I did it this way because this is what I was able to learn from the available tutorials at the time.
However, it seems wasteful because I don't really want the non-matched records at all. Is there a way to tell SSIS to discard the non-matched records entirely rather than store them in a table?
The lookup dialog doesn't appear to give me an option for "ignore non-matches."
Is there some way to achieve this desired behavior?
If lookup = match, insert matched records into table (as currently done)
If lookup not a match, ignore (or discard) non-matched records
Leave Redirect rows to no match output as you currently have specified.
Select the "non-matched" branch and delete the destination.
Done.
Really, that's it. The rows will still be in the memory buffers of your data flow but they won't carry to the Match destination as they'll be logically segmented.
Personally, I have a Row Count wired up so I can count the original Rows, the matched rows and the unmatched rows. It helps me audit how the package has performed over time but there's nothing wrong with not using an output stream from a component.
I am pretty new to SSIS and BI in general, so first of all sorry if this is a newbie question.
I have my source data for the fact table in a csv, so I want to match the ids against the surrogate keys in lookup tables.
The data structure in the csv is like this
... userId, OriginStationId, DestinyStationId,..
What I am trying to accomplish is to match the data against my lookup table. So what I am doing is
Reading Lookup data using OLE DB Source
Reading my csv file
Sorting both inputs by the same field
Doing a left join by Id, in order to get the SK
This way, if there is no match (aka can't find the surrogate key) I can redirect that to a rejected csv and handle it later.
something like this:
(sorry for the spanish!)
I am doing this for each dimension, so I can handle each one with different error codes.
Since OriginStationId and DestinyStationId are two values from the same dimension (they both match against the same lookup table), I wanted to know if there's a way to avoid reading two times the data from the table (I mean, not to use two ole db sources to read twice the data from the same table).
I tried adding a second output to the sort but I am not allowed to. The same goes to adding another output from OLE DB Source.
I see there's an "cache option", is the best way to go ? (Although it would impy creating anyway another OLE DB source.. right?)
The third option I thought of was joining by the two fields, but since there is only one field in the lookup table (the same field) I am getting an error when I try to map both colums from my csv against the same column in my Lookup table
There are columns missing with the sort order 2 to 2
What is the best way to go for this ?
Or I am thinking something incorrectly ?
If something was not clear let me know and I'll update my question
Any time you wish you could have multiple outputs from a component that only allows one, all you have to do is follow that component with the Multicast component, whose sole purpose is to split a Data Flow stream into multiple outputs.
Gonzalo
I have just used this article on how to derive columns for a data warehouse building:- How to Populate a Fact Table using SSIS (part 1).
Using this I built a simple package that reads a CSV file with two columns that are used to derive separate values from the same CodeTable. The CodeTable has two fields Id and Description.
The Data Flow has two "Lookup" tasks. The first one joins the attribute Lookup1 against the Description to derive its Id. The second joins the attribute Lookup2 against the Description to derive a different Id.
Here is the Data Flow:-
Note the "Data Conversion" was required to convert the string attributes from the CSV file into "Unicode string [DT_WSTR]" so they could be joined to the nvarchar(50) description attribute in the table.
Here is the Data Conversion:-
Here is the first Lookup (the second one joins "Copy of Lookup2" to the Description):-
Here is the Data Viewer output with the to two derived Ids CodeTableFirstId and CodeTableSecondId:-
Hopefully I understand your problem and this is of use to you.
Cheers John
I'm going to do my best to try to explain this. I currently have a data flow task that has an OLE DB Source transferring data from a table from a different database to a table to another database. It works fine but the issue I'm having is the fact that I keep adding duplicate data to the destination table.
So a CustomerID of '13029' with an amount of '$56.82' on Date '11/30/2012' is seen in that table multiple times. How do I make it so I can only have unique data transferring over to that destination table?
In the dataflow task, where you transfer the data, you can insert a Lookup transformation. In the lookup, you can specify a data source (table or query, what serves you best). When you chose the data source, you can go to the Columns view and create a mapping, where you connect the CustomerID, Date and Amount of both tables.
In the general view, you can configure, what happens with matched/non matched row. Simply take the not matched output and direct it to the DB destination.
You will need to identify what makes that data unique in the table. If it's a customer table, then it's probably the customerid of 13029. However if it's a customer order table, then maybe it's the combination of CustomerId and OrderDate (and maybe not, I have placed two unique orders on the same date). You will know the answer to that based on your table's design.
Armed with that knowledge, you will want to write a query to pull back the keys from the target table SELECT CO.CustomerId, CO.OrderId FROM dbo.CustomerOrder CO If you know the process only transfers data from the current year, add a filter to the above query to restrict the number of rows returned. The reason for this is memory conservation-you want SSIS to run fast, don't bring back extraneous columns or rows it will never need.
Inside your dataflow, add a Lookup Transformation with that query. You don't specify 2005, 2008 or 2012 as your SSIS version and they have different behaviours associated with the Lookup Transformation. Generally speaking, what you are looking to do is identify the unmatched rows. By definition, unmatched means they don't exist in the target database so those are the rows that are new. 2005 assumes every row is going to match or it errors. You will need to click the Configure Error Output... button and select "Redirect Rows". 2008+ has an option under "Specify how to handle rows with no matching entries" and there you'll want "Redirect rows to no match output."
Now take the No match output branch (2008+) or the error output branch (2005) and plumb that into your destination.
What this approach doesn't cover is detecting and handling when the source system reports $56.82 and the target system has $22.38 (updates). If you need to handle that, then you need to look at some change detection system. Look at Andy Leonard's Stairway to Integration Services series of articles to learn about options for detecting and handling changes.
Have you considered using the T-SQL MERGE statement? http://technet.microsoft.com/en-us/library/bb510625.aspx
It will compare both tables on defined fields, and take an action if matched or not.
This is quite a strange problem, wasn't quite sure how to title it. The issue I have is some data rows in an SSIS task which need to be modified depending on other rows.
Name Location IsMultiple
Bob England
Jim Wales
John Scotland
Jane England
A simplifed dataset, with some names, their locations, and a column 'IsMultiple' which needs to be updated to show which rows share locations. (Bob and Jane's rows would be flagged 'True' in the example above).
In my situation there is much more complex logic involved, so solutions using sql would not be suitable.
My initial thoughts were to use an asyncronous script task, take in all the data rows, parse them, and then output them all after the very last row has been input. The only way I could think of doing this was to call row creation in the PostExecute Phase, which did not work.
Is there a better way to go about this?
A couple of options come to mind for SSIS solutions. With both options you would need the data sorted by location. If you can do this in your SQL source, that would be best. Otherwise, you have the Sort component.
With sorted data as your input you can use a Script component that compares the values of adjacent rows to see if multiple locations exist.
Another option would be to split your data path into two. Do this by adding a Multicast component. The first path would be your main path that you currently have. In the second task, add an Aggregate transformation after the Multicast component. Edit the Aggregate and select Location as a Group By operation. Select (*) as a Count all. The output will be rows with counts by location.
After the Aggregate, Add a Merge Join component and select your first and second data paths as inputs. Your join keys should be the Location column from each path. All the inputs from path 1 should be outputs and include the count from path 2 as an output.
In a derived column, modify the isMultiple column with an expression that expresses "If count is greater than 1 then true else false".
If possible, I might recommend doing it with pure SQL in a SQL task on your control flow prior to your data flow. A simple UPDATE query where you GROUP BY location and do a HAVING COUNT for everything greater than 1 should be able to do this. But if this is a simplified version this may not be feasible.
If the data isn't available until after the data flow is done you could place the SQL task after your data flow on your control flow.