I am writing a basic file dump from one database to another. I am using SSIS 2008 and creating several packages to transform the data I have from a MSSQL 2010 database to a MYSQL 5.1 database.
All the connections are set up and records can be tranfered between the two databases but I would like to use temp tables in the transform processes and use the temp table as the MSSQL source in a dataflow task to dump the table in an awaiting MYSQL table.
I have been having problems setting this up. I am using an OLEDB connection and have set the RetainSameConnection property as well as the DelayValidation property to true. When setting up the source figure as the source from the MSSQL database I cannot find the temp table I have created in an earlier task from the control flow. I am using the same connection manager for these two tasks.
Anyone have any ideas or experience with this?
As a simple example one task does..
SELECT *
INTO #TMP
FROM CUSTOMERS
(This is a simplified example and I relize in this case I could just use the Customers table so bear with me)
Is it possible to use this temp table in a dataflow operation as the source table?
As I mentioned in my comment, not much of a solution and more of a workaround. SSIS uses the shape of result sets to bind properties in tasks. As temp tables are not always available in the database this can cause errors in SSIS even if you set DelayValidation to true.
My solution is to create an SSIS schema in whichever database you're connecting to. The reasons for doing so are security and clear separation of objects that are only used within SSIS packages - primarily staging tables.
Instead of throwing tables in your dbo schema (you shouldn't be anyway, shame on you) you'd create them in the SSIS schema. A typical data flow would truncate the table when it begins, load values and perform whatever operations are required, optionally truncating it when complete. As long as the table is always available SSIS can examine the shape of result sets.
You should not use temp tables as the source as it will not recognize the columns for the select. use table variables or CTEs instead.
Related
I am implementing a SSIS package and currently trying to do the following.
Truncate the destination table
Fetch the data by executing the stored procedure and insert it into the destination table.
I have created an Execute SQL task to address step 1 and dataflow with oledb source and oledb destination to address the second point. It been working successfully so far but isn't working for one my stored procedure that uses temp tables.
When I edit the oledb source and click the preview button, I get the error no column returned
I know that SSIS has an issue with generating column while executing stored procedures that depend on temp tables. I have converted the stored proc to use temporary table variables and its now able to return columns in SSIS when I do a preview. The only downside is that the stored procedure is taking longer time to execute. Its taking 1 hour 15 mins as compared to 15 mins while using temp tables.
I did see a suggestion to use SET FMTONLY before executing the stored procedure as an alternate solution to changing to temp table variables but that didn't seem to work as I am getting syntax or permission denied error.
Could somebody tell me a solution to my problem which does not compromise on the performance.
Sounds like you've already read all the approaches to using Temp tables in SSIS, including the IF 1=0... trick? If you haven't seen that one yet, google it.
You say that using Table Variables causes your stored procedure to take about 5 times longer than using Temp Tables. The most likely reason for that is that you are indexing your temp tables but not your table variables. If you didn't know that table variables can be indexed, they can. You might try that.
Finally, a solution that you haven't mentioned is that you can replace your temporary table with a real table that gets truncated when you're done using it.
Short comment:
Try EXEC WITH RESULT SETS and specify the metadata yourself for a proc with temp tables; or use the Script Component as a source and specify the Output columns yourself.
Long comment:
Technically speaking, it is the driver/database you are using in SSIS that would decide the behavior when working with temp tables.
Metadata is an important factor when using SSIS's pipeline components. By metadata, I mean the names of the columns, their data types etc that a pipeline component uses. When designing a data flow, someone/something should provide this metadata to the components that require it.
In most cases, SSIS automatically retreives the metadata. Components that do not connect to a external data source, like Conditional Split etc, get their metadata from the other components they are connected to. For the pipeline components that connect to a external data source (like Oledb source, oledb destination, Lookup etc.), SSIS provides a mechanism to get this metadata without human involvement. This mechanism involves the driver connecting to the database and retrieving the metadata of the output. If the driver/database is capable of returning the metadata, then that metadata is used. If the driver/database is incapable, then you get the errors you are seeing. The rest of my comments are based on the assumption that you are using a SQL Server database in your question.
When working with a SQL Server database in SSIS, typically, we use the native client drivers provided by Microsoft. When trying to get the metadata, these drivers try to get the metadata without actually executing the SQL Statement (actual execution can have side effects; and also, might take more than a few seconds/minutes/hours; and you dont want side effects and long wait times during package design time.) So to get the metadata, the driver relies on the metadata of the actual objects used in the sql command. If the command uses a physical table or view, SQL Server already has the metadata available and can supply it to the driver. If it is a temp table, SQL Server does not have the metadata until it can create the temp table. If using FMT ONLY option, you can use it in such a way to create the temp tables, but avoid any heavy processing/side affects and thus be able to retrieve metadata without penalties. Post 2012, these native client drivers rely on some newer functionality to retrieve metadata than the drivers before 2012. In 2012 and after, the driver uses the sp_describe_first_result_set proc to retrieve metadata. So, whether you can get metadata or not is determined by the ability of the sp_describe_first_result_set proc.
So while SSIS can automatically get the metadata (because of the driver/database), it does not automatically get the metadata in some cases (again because of the driver/database). In cases involving the second scenario, some other process (typically a human) can help the driver infer metadata or provide the metadata to the component directly.
To help the driver, in case of SQL Server 2012 and after, you can use the WITH RESULTSETS clause to specify the output metadata. When this clause is present, the driver will use it and doesnt try to query the metadata from system objects; and thus avoid the error which you would otherwise get. If you are using the drivers that came with SQL Server 2008, you can use FMT ONLY. This option is at the driver/database level.
Another option could be to use a Script Component as the Source and in the Output columns, you can specify the columns/metadata. SSIS would not try to retrieve metadata from the datasource in this case, but would rely on the definitions you provided in the Output section of the Script Component.
As you can see, both options involve a human (or some other process) specifying the metadata instead of SSIS trying to retrieve the metadata in an automated fashion. I would prefer the first option if working with SQL Server and the second option if working with databases like MySql.
I can only find a solution for using temp table in OLE DB source.
But I can't find a solution for ADO.NET source. How can I successfully use temp table in the ADo.NET source in SSIS package?
I find working with temporary tables in SSIS more pain than they are usually worth. I hope your experience is better.
Create an ADO.NET connection. In the properties of the Connection Manager set the value of RetainSameConnection from false to true. This will allow the temporary table created to be in existence for the duration of the package execution by preventing connection pooling from swapping out threads.
My trouble extends from getting the metadata set up correctly. To get around this, I create a variable, QuerySource, that queries a physical table that mirrors what the temporary table will look like. SELECT S.src_id, S.src_value FROM dbo.SRC AS S; This allows the data flow to establish the correct meta data for the downstream components. I manually use this query in the ADO.NET source. Once that's done, I will need to change the query to use the temporary table, ##SRC. Unlike the OLE DB Source component, you cannot set this property inside the Data Flow task.
Once the data flow work is completed, back in the Control Flow, view the Properties of the Data Flow Task. Change the Delay Validation from false to true. This will prevent any design time validation from firing which is needed once we remove the non-temporary table "scaffolding." Next find the Expressions and click the ellipses (...). In the drop down, you should see the name of your ADO.NET source. I had renamed mine so I saw [ADONET Src].[TableOrViewName] and [ADONET Src].[SqlCommand] in the drop down list. I selected [ADONET Src].[SqlCommand] and as my value, I used #[User::SrcQuery].
I ran the package to ensure it still worked. It did. I then changed the value of my query to be SELECT S.src_id, S.src_value FROM ##SRC AS S; I reran and this time it correctly pulled data from my temporary table.
If you are using SQL Server 2012 as your source, you might be able to make it easier on yourself by using the WITH RESULT SETS option of the EXECUTE statement to explicitly describe your temporary tables metadata.
I have an SSIS application that needs to get data from 2 databases of different servers (not link). I need to get the match names and DOB records between 2 database then use the results to insert/update a table.
My initial approach is to use OLE DB source then Merge Join and put the results to recordset. Then on controlflow, use the results of the recordset to insert/update a table. But I can't see the recordset at the control flow.
Alternative solution is to create temp tables. But the temp tables are not visible since they reside at the tempdb database of each servers.
What is a better approach for this problem?
what do you mean by put the results to recordset?
If you join two sources on the data flow using a join, that "recordset" on the join will only be available during the current dataflow. You cant use it on the control flow after the data flow is finisehd.
why cant you just insert the resultset on the destination DB? You can perform any other transform operation on the same data flow and insert the result on the destination database.
Or, if you really need to do something that can only be done on the control flow before insert the data, you can yes, insert the recordset on a temp table on the destination using a oleDBDestination and access in on another dataflow (not a very good approach, though)
In this case, I would keep a database around for work table or create a schema for those work tables.
Next, add a SQL control flow task that truncates the table that will hold the intermediate result. After this, load the intermediate result set into the table, do the operation and optionally, truncate the table again.
The recordset destination is fine for smaller datasets. But if you plan to use it for larger datasets that dont fit memory it will be very slow.
If you dont have a database/schema that can serve as a workspace, you could use RAW files to hold the intermediate result. Those are very fast too.
I would like to bring in an XML source and do data conversion and update it in a table. Data from this table will be used to update another table. How to accomplish this in SSIS?
I understand the first two steps. But lost after that.
XML Source (under dataflow task)
Data Conversion
OLE DB Destination? (If I use OLE DB Destination, then I cannot use that as a source again to update another table). What component should I be using to accomplish this?
TIA
Within a dataflow you can split the records to go to multiple tables using either a conditional split (if you want some records to go one way and some to go another way) or a mulicast task if you want all records to go to both destinations. We use a multicast to create two staging tables, one where the raw data from the file will stay and one where the data will be cleaned and transformed before going into our prod tables. This enables us to easily research if some problem data that came in was due to our transformation process (a bug) or bad data being sent (a problem at the client end, but which might require more steps to handle if they can't fix).
You can also have multiple data flows that all have the same source. Or you can insert to one staging table and then have a second data flow or exec SQL task to move that data to where you want it.
Use the OLE DB Destination to inject your XML source data into your staging table. Then, in your control flow use an Execute SQL task after your data flow task to execute a stored procedure or T-SQL script to move your data from the staging table into the production table(s) and truncate the staging table if required.
I've found that SSIS is great for ETL work, but moving data around inside a DB or aggregation work is best carried out using T-SQL in stored procs. Easier to write, control and you know you're not going to have any RBAR shenanigans you can happen upon in a DFT.
YMMV
I need to convert data that already exists in a MySQL database, to a SQL Server database.
The caveat here is that the old database was poorly designed, but the new one is in a proper 3N form. Does any one have any tips on how to go about doing this? I have SSMS 2005.
Can I use this to connect to the MySQL DB and create a DTS? Or do I need to use SSIS?
Do I need to script out the MySQL DB and alter every statement to "insert" into the SQL Server DB?
Has anyone gone through this before? Please HELP!!!
See this link. The idea is to add your MySQL database as a linked server in SQL Server via the MySQL ODBC driver. Then you can perform any operations you like on the MySQL database via SSMS, including copying data into SQL Server.
Congrats on moving up in the RDBMS world!
SSIS is designed to do this kind of thing. The first step is to map out manually where each piece of data will go in the new structure. So your old table had four fields, in your new structure fileds1 and 2 go to table a and field three and four go to table b, but you also need to have the autogenerated id from table a. Make notes as to where data types have changed and you may need to make adjustments or where you have required fileds where the data was not required before etc.
What I usually do is create staging tables. Put the data in the denormalized form in one staging table and then move to normalized staging tables and do the clean up there and add the new ids as soon as you have them to the staging tables. One thing you will need to do if you are moving from a denormalized database to a normalized one is that you will need to eliminate the duplicates from the parent tables before inserting them into the actual production tables. You may also need to do dataclean up as there may be required fileds in the new structure that were not required in the old or data converstion issues becasue of moving to better datatypes (for instance if you stored dates in the old database in varchar fields but properly move to datetime in the new db, you may have some records which don't have valid dates.
ANother issue you need to think about is how you will convert from the old record ids to the new ones.
This is not a an easy task, but it is doable if you take your time and work methodically. Now is not the time to try shortcuts.
What you need is an ETL (extract, transform, load) tool.
http://en.wikipedia.org/wiki/Extract,_transform,_load#Tools
I don't really know how far an 'ETL' tool will get you depending on the original and new database designs. In my career I've had to do more than a few data migrations and we usually always had to design a special utility which would update a fresh database with records from the old database, and yes we coded it complete with all the update/insert statements that would transform data.
I don't know how many tables your database has, but if they are not too many then you could consider going the grunt root. That's one technique that's guaranteed to work after all.
If you go to your database in SSMS and right-click, under tasks should be an option for "Import Data". You can try to use that. It's basically just a wizard that creates an SSIS package for you, which it can then either run for you automatically or which you can save and then alter as needed.
The big issue is how you need to transform the data. This goes into a lot of specifics which you don't include (and which are probably too numerous for you to include here anyway).
I'm certain that SSIS can handle whatever transformations you need to do to change it from the old format to the new. An alternative though would be to just import the tables into MS SQL as-is into staging tables, then use SQL code to transform the data into the 3NF tables. It's all a matter of what your most comfortable with. If you go the second route, then the import process that I mentioned above in SSMS could be used. It will even create the destination tables for you. Just be sure that you give them unique names, maybe prefixing them with "STG_" or something.
Davud mentioned linked servers. That's definitely another way that you can go (and got my upvote). Personally, I prefer to copy the tables over into MS SQL first since linked servers can sometimes have weirdness, especially when it comes to data types not mapping between different providers. Having the tables all in MS SQL will also probably be a bit faster and saves time if you have to rerun or correct portions of the data. As I said though, the linked server method would probably be fine too.
I have done this going the other direction and SSIS works fine, although I might have needed to use a script task to deal with slight data type weirdness. SSIS does ETL.