Exporting Data Using BCP
BCP, or bulk copy program, has been around in SQL Server for a long time. It is a great way to export large quantities of data very quickly from SQL Server. It can be used to export entire tables or even a custom query. In this post we will focus on doing some simple commands to export data. This is by no means a complete and comprehensive look at BCP. My only intention with this post is to get you started and maybe provide a quick syntax reference for doing BCP in the future.
The obvious choice to move data out to a flat file may be SSIS. BCP could not be any more of a polar opposite in actually implementing the data export in that SSIS is a completely developed in a GUI and BCP is completely developed at the command prompt.
To get started open up a new command prompt window on your computer. You may want to go ahead and run it as administrator in case you want to put the file someplace like the C: drive and have UAC turned on. If you simply type BCP at the command prompt a series of available commands will be displayed. We will only touch on a couple of those:
You can see in the screenshot the basic syntax for BCP is [What to Export] [in or out] [file]
BCP AdventureWorks.Production.Product out C:Production_Product.txt
The second parameter can actually have one of four values:
- in – Copy data into a table or view from a file
- out – Copy data from a table or view to a file
- queryout – Copy data from a query to a file (query must be provided enclosed in quotes, not a table or view name)
- format – Creates a format file based on the table, view or query specified
There are several other parameters you will want to be sure to include keeping in mind each is case sensitive:
- -S ServerNameInstanceName
- -U Username and -P Password
- -T Windows Authentication
- Data Types
- -c Character data types
- -n Uses the native data types from the source system
- Do not specify anything and you will be prompted to provide a data type for each column
Now for a couple of samples:
For each of these I am going to be using windows authentication to connect to a named instance on my local machine. This can connect to other servers however and the files can also be sent to a network share as well.
Table Export: BCP AdventureWorks.Production.Product OUT C:ProductionProduct.txt -S localhostSQL2008R2 -T -c
Notice that 504 rows were exported in well under a second at 504,000 rows per second.
Query Export: BCP “SELECT * FROM AdventureWorks.Production.ProductModel” QUERYOUT C:ProductionProductModel.txt -S localhostSQL2008R2 -T -c
The results in this case are similar: 128 rows exported, still under a second and 1,376 rows per second.
Notice what happens when providing a query and specifying OUT instead of QUERYOUT:
Unfortunately the error is not all that great, we are just told that an error occurred while processing the command line.
Just to show what happens when exporting a table with more than just a couple of records here is a screenshot of the export from ContosoRetailDW.dbo.FactOnlineSales
Hope this sheds some light on exporting data with BCP. Be on the lookout for some information coming on importing data with BCP as well as a performance comparison between BCP and SSIS direct to a flat file.
Want to explore the BCP options in more detail? Head over to the MSDN page: http://msdn.microsoft.com/en-us/library/ms162802(v=sql.105).aspx