What is the difference between control flow and data flow in a SSIS package along with some examples please.
Thanks.
In data flow task, it is mandatory that data needs to be made flown/transferred from a source to destination. Whereas in control flow task it is not.
Control Flow:
Control Flow is part of SQL Server Integration Services Package where you handle the flow of operations or Tasks.
Let's say you are reading a text file by using Data Flow task from a folder. If Data Flow Task completes successfully then you want to Run File System Task to move the file from Source Folder to Archive Folder. If Data Flow Task failed then you want to send email to your users by using Send Mail Task. The Precedence Constraints are used to control the execution flow.
Data Flow:
Data Flow is the part of SQL Server Integration Services Package, where data is extracted by using Data Flow Sources ( OLE DB Source, Raw File Source, Flat File Source , Excel Source etc.). After extacting data Data Flow Transformations such as Data Conversion, Derived Column, Lookup, Multicast,Merge etc are used to implement different business logics and finally written to Data Flow Destinations (OLE DB Destination, Flat File Destination,Excel Destination,DataReader Destination ADO NET Destination etc.)
Take a look at This post for more details.
Click on the Control Flow Tab and observe what items are available in Tool Box
Similarly Click on the Data Flow Tab observe what items are available
Related
I'm writing a (what I thought to be a) simple SSIS package to import data from a CSV file into a SQL table.
On the Control Flow task I have a Data Flow Task. In that Data Flow Task I have
a Flat File Source "step",
followed by a Data Conversion "step",
followed by a OLE DB destination "step".
What I want to do is to move the source CSV file to a "Completed" folder or to a "Failed" folder based on the results of the Data Flow Task.
I see that I can't add a File System step inside the Data Flow Task, but I have to do it in the Control Flow tab.
My question is how do I do a simple thing like assign a value to a variable (I saw how to create variable and assign them a value at the bottom pane of Data Tools (2012)) depending of if the "step" succeeds or fails?
Thanks!
(You can tell by my question that I'm an SSIS rookie - and don't assume I can write a C# script, please)
I have used VB or C# scripts to accomplish this myself. Since you do not want to use scripts I would recommend using a different path for the project to flow. Have your success path lead to moving the file to completed and failure path lead to moving the file to failed. This keeps it simple and accomplishes what you are looking for.
I'm working with legacy tsql code that outputs to txt files.
For security reasons, I'm replacing these outputs with SSIS packages.
I've gotten most of them to work, but one particular one gives me the following error:
TITLE: Microsoft Visual Studio
Cannot create connector.
The destination component does not have any available inputs for use in creating a path.
The data flow itself is very simple. OLE DB Source runs an SQL command, then outputs to a flatfile source that points to an existing txtfile that was created by the TSQL.
Anyone know what the error means in regards to the available inputs?
Your SSIS toolbox is divided into 3 general groupings (pre 2012/2014)
Sources
Transformations
Destinations
A source has 1 to N output paths. Nothing can feed into a source. Things can only consume what a Source emits.
A Transformation does not generate* rows, it accepts rows from an upstream provider (either a Source or another Transformation). A Transformation has 1 to N output paths.
A Destination is the terminus for data. I'm not aware of any destinations that accept more than one input. It has one optional output path, Error.
Your problem, therefore, is that you are trying to route data into a Source. Change that to a Flat File Destination.
Replace the Flat File Source with a Flat File Destination task. Click on the RowCount task and drag the green arrow to the new destination.
I'm new to SSIS. When I try to load data from an Excel File and there is another data flow task in the same package, it just fills the table with null data, e.g., dim_Alarm(null,null,null,null). However, when I try adding a new package and the data flow task is alone in the package, then the data is loaded.
Look at the Connection Manager for the Excel Source for the dataflow that is returning null data. There is probably some difference - maybe a typo error? - between the one that returns null data, and the one that loads the data from the file.
It is unlikely that the presence or absence of the other data flows is causing this problem, unless they are hitting the same Excel file, or they are hitting the same database table dim_Alarm. It is much more likely that there is some small difference between the data flow that loads nulls and the data flow that works (in the empty package).
You can also add a Data Viewer to the data flow that isn't behaving as you expect. The Data Viewer goes on one of the arrows between transformations in the data flow. When you run the package in BIDS, the Data Viewer will show you the data that flows through that point. If the data is missing, you may be able to see where it got lost. Is there data coming out of the Excel Source, but after the next transformation there is no more data? Then that is where the problem is.
I want to execute the XML source after a script component is complete n SSIS data flow. i.e based on whether the script fails or passes the xml source flow should start (in the data flow). Is there any simpler way to do it.
I cannot create a connector because XML source doesn't have any inputs.
Got it, i can add a script task instead of script component in dataflow. And make a flow from script task to data flow.
I am used to DTS Pkgs where i can just write to a text file using a data transform task.
How can i do the equivalent of this in SSIS?
Thanks.
You can use the Data Flow task in SSIS. Create the Data Flow task. Add an appropriate source component to get the data. Then add a Flat File Destination. The destination can be configured to your file requirements. Connect the two objects and map the columns.