how do you break out of a foreach loop

  • I've got a foreach loop container looping through a folder that has zipped files with both a 2014-06-20 and 2014-06-21 date as part of their filenames. I want to unzip the Jun 20 ones first, the Jun 21 ones second. I've got it working to the point that first the filenames having 2014-06-20 are getting unzipped, but after that I don't know how to make it terminate the foreach loop so that I can update the Timetbl with to show IsProcessed = 1 for the 2014-06-20 date.

    How do you break out of a foreach loop once every file meeting the date requirement has been processed once?

    Here's what I have so far:

    SourceFolder looks like this:

    File1_2014-06-20.txt.zip

    File1_2014-06-21.txt.zip

    File2_2014-06-20.txt.zip

    File2_2014-06-21.txt.zip

    File3_2014-06-20.txt.zip

    File3_2014-06-20.txt.zip

    I created a TimeTbl to contain all dates, with column as to whether that date was processed or not. DDL:

    CREATE TABLE [dbo].[Timetbl](

    [TimeCol] [datetime] NULL,

    [IsProcessed] [bit] NULL

    ) ON [PRIMARY]

    GO

    inserted into table, 4 rows

    insert into Timetbl

    values

    ('2014-06-18', 1),

    ('2014-06-19', 1),

    ('2014-06-20', 0),

    ('2014-06-21', 0);

    PACKAGE

    2 package level variables:

    name:datePart\scope: Package1\datatype: string

    name: zippedFile\scope: Package1\datatype: string

    Control Flow:

    Execute SQL Task: make a Datepart to use in Foreach Loop containers FileNameRetrieval expression

    General

    Result Set: single row

    connectionType: oledb

    sqlsourcetype: direct input

    sqlstatement:

    select top 1 CONVERT(varchar(10), TimeCol, 20) as TimeCol

    from Timetbl

    where IsProcessed = 0

    order by timecol asc

    Parameter Mapping

    [nothing]

    Result Set

    Result Name: TimeCol

    Variable Name: User::datePart

    Expressions

    [nothing]

    Foreach Loop Container

    Collection

    Enumerator: Foreach File Enumerator

    Expressions: Expressions: FileNameRetrieval\"*"+@[User::datePart]+".txt.zip"

    Folder: C:\SourceFolder

    Files: *.txt.zip

    VariableMappings:

    variable: User::zippedFile\index:0

    Inside the Foreach Loop Container

    Execute Process Task Editor

    Process

    Executable C:\Program Files (x86)\7-Zip\7z.exe

    Arguments e -oC:\Users\me\Downloads\test2

    Expressions

    Arguments\"e " +@[User::zippedFile]+ " " +"-oC:\\Users\\me\\Downloads\\test2"

  • A foreach loop in SSIS is, by definition, an iteration of n items, in which n is defined at the beginning of the loop. So you can't really exit a foreach loop prematurely. However, you could configure your package to effectively do nothing in a loop.

    I blogged about the scenario you describe here some time back: http://www.timmitchell.net/post/2009/09/16/skipping-items-in-a-foreach-loop/. Essentially, you can use an SSIS expression on your precedence constraint to check some condition before executing anything else in that iteration of the loop. You could interrogate your date table that you mentioned in each loop and see if the current date has already been loaded. You wouldn't be terminating the loop early - the loop would still execute once for each file in the target directory. However, binding an expression to that precedence constraint would allow you to conditionally skip files representing dates that have already been processed.

    Hope this helps!

    Tim Mitchell, Microsoft Data Platform MVP
    Data Warehouse and ETL Consultant
    TimMitchell.net | @Tim_Mitchell | Tyleris.com
    ETL Best Practices

  • Tim Mitchell (7/29/2014)


    A foreach loop in SSIS is, by definition, an iteration of n items, in which n is defined at the beginning of the loop. So you can't really exit a foreach loop prematurely. However, you could configure your package to effectively do nothing in a loop.

    I blogged about the scenario you describe here some time back: http://www.timmitchell.net/post/2009/09/16/skipping-items-in-a-foreach-loop/. Essentially, you can use an SSIS expression on your precedence constraint to check some condition before executing anything else in that iteration of the loop. You could interrogate your date table that you mentioned in each loop and see if the current date has already been loaded. You wouldn't be terminating the loop early - the loop would still execute once for each file in the target directory. However, binding an expression to that precedence constraint would allow you to conditionally skip files representing dates that have already been processed.

    Hope this helps!

    Just making your link easier to use:

    http://www.timmitchell.net/post/2009/09/16/skipping-items-in-a-foreach-loop/

  • Thanks Lynn - forgot to add the hyperlink.

    Tim Mitchell, Microsoft Data Platform MVP
    Data Warehouse and ETL Consultant
    TimMitchell.net | @Tim_Mitchell | Tyleris.com
    ETL Best Practices

  • Tim Mitchell (7/29/2014)


    Thanks Lynn - forgot to add the hyperlink.

    Not a problem. Glad to help out.

  • Tim Mitchell (7/29/2014)


    A foreach loop in SSIS is, by definition, an iteration of n items, in which n is defined at the beginning of the loop. So you can't really exit a foreach loop prematurely. However, you could configure your package to effectively do nothing in a loop.

    I blogged about the scenario you describe here some time back: http://www.timmitchell.net/post/2009/09/16/skipping-items-in-a-foreach-loop/. Essentially, you can use an SSIS expression on your precedence constraint to check some condition before executing anything else in that iteration of the loop. You could interrogate your date table that you mentioned in each loop and see if the current date has already been loaded. You wouldn't be terminating the loop early - the loop would still execute once for each file in the target directory. However, binding an expression to that precedence constraint would allow you to conditionally skip files representing dates that have already been processed.

    Hope this helps!

    That's basically what I had to do in a number of packages I'm working with now.



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  • It sounds a lot like you really need to have two nested loops,

    Loop 1 ) foreach date

    .. Loop 2) foreach file matching date

    MM



    select geometry::STGeomFromWKB(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