How To – Tasks and Transformations: Foreach File Loop

Written by Varigence Blog on 5.19.2011

TAGS: MistBISSIS

Share

I left off last time discussing the SSIS File System task. Although that task does enable convenient bulk file operations, it’s limited due to its lack of wildcard support. Say I need a workflow that routinely copies all of the previous hour’s work orders to another location. By itself, the File System task is only helpful if the work orders are already grouped, which is unlikely. To help handle these more complicated operations, SSIS has a Foreach Loop Container task, which I will explore in this post.

Background:

The Foreach Loop Container task allows you to iterate over a list of items and run additional tasks on each item that’s enumerated. This post is going to focus solely on file enumeration, which is one of several enumeration options offered by the Foreach Loop container. In fact, the Foreach Loop container can enumerate all of the following types:

Enumerator Purpose ADO Enumerate rows in tables ADO.NET Schema Rowset List schema information about a data source, such as the list of tables in a SQL Server database File Enumerate files in a folder From Variable Enumerate the enumerable object that a variable contains. For instance, if a variable contains a DataTable or an array, you can enumerate its values. Item List items in a collection, such as the names of executables in an Execute Process task NodeList List the items in a XPath expression result set SMO Enumerate SMO objects, such as the views in a SQL database

In Biml, each enumerator type is associated with its own task. Thus, instead of using the Foreach Loop Container task, you would use the Foreach File Loop task.

The Foreach Loop Container task enumerates each file in a directory, allowing you to run other tasks on those files. This task also allows you to filter the files you want to enumerate using wildcards, whereas the File System task is limited to either all files in a directory or a particular file. That’s the difference that’s going to enable more flexible file operations.

The scenario I’m going to demonstrate is archiving all .csv files in a directory.

Using BIDS:

To get started, you need to find the Foreach Loop Container in the Toolbox.

alt text here…

Drag and drop the task on the package’s design surface. Notice that this task has some differences from the previous tasks I’ve demonstrated. First, there’s no red X icon; in fact, the error list remains empty after adding the task. Second, this is the first task with a beige area underneath its name. The beige area is where you can add other tasks that reside in the container. When the task enumerates over the list of files, it will execute the workflow within its container for each file.

alt text here…

Double click on the task to open its editor dialog.

alt text here…

Click on the Collection list item on the left side of the dialog to display the Collection settings.

alt text here…

By default, the Foreach Loop task uses a file enumerator, which is what you want. Note that if you click on the Foreach File Enumerator value, you’ll see a down arrow button.

alt text here…

Clicking on the arrow button opens a dropdown that lets you choose a different enumerator.

alt text here…

Beneath the Foreach Loop Editor property grid is the Enumerator configuration group. This is where you specify what files to enumerate.

alt text here…

For this scenario, you first need to specify the directory that contains the .csv files to be archived. To do that, enter the folder path in the Folder text box. Note that you can also use the Browse button to display a folder selector dialog to help retrieve the folder path.

alt text here…

This path indicates that the task will enumerate files within the ForEachContainerFiles directory.

With the folder path identified, you now need to specify the files to enumerate. The default value indicates that all files in the folder path will be listed. However, the goal here is to only archive .csv files, skipping files with other types. To specify just .csv files, type in *.csv to specify that file extension. The star character indicates that zero or more characters are acceptable. Be sure to remove the star on the right size as .csv could unintentionally return files as such bob.csvc.

Note that the Files textbox isn’t limited to specifying file extensions. Say you had files with dates embedded in their file name, like sales03-05-11.csv. You could use the Files text box to just archive files with dates in October or files of a particular year.

Beneath the Files text box is the Retrieve file name group box. This group box lets you specify the format in which each file is returned. There are three formats to choose from:

Format Example Fully qualified C:varigenceSamplesT&T BlogForEach ContainerFilesresults1.csv Name and extension results1.csv Name only results1

Since you will be performing file operations, having the fully qualified path will be useful. Thus, click on the Fully qualified radio button to select that format.

Finally, the Traverse subfolders checkbox lets you decide if the Foreach Loop Container will search subfolders, beneath the folder path, for files that meet your criteria.

alt text here…

With the enumerator setup done, you now need to store the current file path as the enumerator proceeds. This can be done using a variable. To set this up, first click on the Variable Mappings list item on the left side of the dialog.

alt text here…

As no variables have been created yet, you’ll need to add one. Do that by clicking inside the Variable cell.

alt text here…

A dropdown button will appear. Click on the dropdown button to open a list that contains a New Variable item.

alt text here…

Click on the New Variable item to open the Add Variable dialog box.

alt text here…

The first change you need to make is the container. This whole Package doesn’t need to know about this variable; just the ForEach Loop container. To change the variable’s container, click on the Container’s down arrow button to open a pop-up.

alt text here…

Expand the tree view nodes in the pop-up to reach the Foreach Loop container that you created. Click on it to select it and then press OK.

Next, I recommend changing the variable’s Name to something clearer, such as CsvFilePath. The other values can remain unchanged.

alt text here…

Press OK to create the variable and dismiss the dialog.

alt text here…

Notice that the CsvFilePath variable has been mapped to a 0 index. While it turns out that this is correct, it’s worth understanding what this means. For the moment, let’s say that instead of enumerating a list of files, you need to iterate over a row set, where each row has some columns.

Name    Street  Zip Code

Row 1 Microsoft 1 Microsoft Way 98052 Row 2 Apple 1 Infinite Loop 95014 Row 3 Intel 2200 Mission College Blvd. 95054

In this case, if you wanted to operate on the Street value for a row, as the enumeration occurs, you would create a variable and map it to index 1. You would map to index 1, instead of index 2, since despite Street being the second column, indexes are zero based. For the file enumerator, despite thinking about it as a list of files, it’s internally treated like a table where each row represents an item in the collection and the table has one column for the file path. Thus, BIDS maps the variable to index 0.

Now you can press OK to dismiss the Foreach Loop editor dialog.

The next step is to place the File System task within the Foreach Loop container so it can run as the list of files is enumerated. To do that, find the File System task in the Toolbox window.

alt text here…

Then drag and drop the File System task on top of the container.

alt text here…

You can review my previous blog post on the File System task for step by step instructions on how to set it up. In brief, start by opening the File System Task editor dialog.

First, change the operation type from Copy file to Move file.

alt text here…

Second, set the Source Connection group’s IsSourcePathVariable to true. That will change the SourceConnection property to SourceVariable. In the SourceVariable dropdown, select User::CsvFilePath.

Third, create a Destination Connection, with its usage type set to Existing Folder. The File Connection’s Folder path should be the directory where the files will be archived.

alt text here…

Your File System task editor dialog should now look like:

alt text here…

You can now try to run your package. But if you do, you’re going to get a build error as the File System task has a red X icon. Checking the error list, you’ll see:

alt text here…

This is because no value was entered for the variable. This is counterintuitive since the whole point of this approach is that the enumerator will populate the variable as it runs. However, the validator isn’t that smart so you’ll need to workaround this bug by giving the variable a value that will be overwritten once the workflow runs. To do that, first click on the Foreach Loop Container task to select it.

alt text here…

Then, open the SSIS menu in the BIDS menu bar and select Variables.

alt text here…

This opens the Variables tool window for the Foreach Loop container. Next, double click on the value cell for the CsvFilePath variable.

alt text here…

In the cell, type in anything, such as Placeholder. Then press enter.

alt text here…

This will resolve the error, although the error list may not immediately reflect it. I had to close my package and reopen it to get the error list to update.

Using Mist:

Now it’s time to discuss implementing a Foreach File loop in Mist.

To start, you’ll need to create a package. If you’re unfamiliar with how to create a package, you can follow the first couple steps in the Mist User Guide’s Creating a Package topic.

Once you’ve opened the package, navigate to the Toolbox tool window.

alt text here…

Notice that there’s a Container group in the tree view. The Foreach File Loop container is within the ForEach sub group. Select and drag the Foreach File Loop container onto the Package’s design surface.

alt text here…

Unlike BIDS, there is a red X icon on the Foreach File Loop container since it has errors.

alt text here…

Mist requires you to provide values for the Folder and FileSpecification properties.

Notice that to the right of the red X icon, there’s a magnifying glass icon. I’ll explain that later in this post.

Click on the Package Details tab to see the tool window’s contents.

alt text here…

Matching the BIDS sample, the first step is to enter the Folder and File Specification for the Foreach File Loop container. You can enter the Folder path in the Folder textbox. You can enter the wildcard, for the files you want enumerated, in the File Specification text box.

alt text here…

The Retrieve File Name format defaults to Fully Qualified so that doesn’t need to change. You can check the Process Subfolders checkbox to enable that behavior.

alt text here…

Next up, you need to create a variable mapping. To do that, go into the ribbon and find the Variable Mapping button.

alt text here…

Notice that the button is in a group named Task Specific. As you select different tasks in a package, the buttons in the Task Specific group will change to be appropriate for the selected task. Press the button to create a variable mapping.

alt text here…

The mapping is added in the Foreach File Loop container’s Variable Parameter Mappings data grid. If you double click on the Parameter Name cell in the mapping’s row, you can change the mapping’s name. If you double click on the variable cell, a combo box will appear, indicating that no variable has been selected.

alt text here…

Clicking on the combo box will bring up a listing of the task’s built-in variables.

alt text here…

Of course, you will want to create a new variable. To do that, return to the ribbon and press the Variable button.

alt text here…

The Variables tool window will be brought to the front of the Mist UI, with a new variable created and already selected. You can change the variable’s name by double clicking on the name cell and then typing in the name you want. To match the BIDS sample, I’ve named the variable CsvFilePath.

alt text here…

Next, return to the package details tool window and in the variable mapping, reopen the Variable combo box. You can now select the CsvFilePath variable.

alt text here…

With that, the Foreach File Loop task is set up.

alt text here…

Notice that in the Variable cell, the variable’s scope is included in the name, meaning that you can easily see the variable is in Foreach File Loop 1, which resides in Package1. Also notice that on the errors tab to the left, there are 0 errors, confirming that every required property has been filled in.

With that done, you can add the File System task within the Foreach File Loop container. Find the File System task in the Toolbox tool window.

alt text here…

Then drag and drop it on top of the Foreach File Loop container.

alt text here…

Now I’m ready to talk about the magnifying glass icon in the Foreach File Loop’s header. If you click on the magnifying glass, you’ll see the following:

alt text here…

The magnifying glass makes the entire design surface dedicated to the Foreach File Loop task. Admittedly, you wouldn’t need this feature for this simple scenario. However, it comes in very handy if you’re implementing a complicated workflow within a container. Instead of having to repeatedly resize the container, or scroll within it, you can easily take advantage of your screen real estate. Returning to the package view is also easy; just click on Package1 in the breadcrumb bar.

alt text here…

To finish the sample, you’ll need to populate the File System task with appropriate values. You can refer to my previous blog post for details on using that task. When done, the File System task’s details editor should look as follows:

alt text here…

If you want to play with this sample, you can download it from here.

More Information:

It’s important to note that if you have a Foreach File Loop where you modify the collection during execution, it can have unintended side effects. Microsoft explicitly warns users that unexpected situations may occur due to files being added, deleted, or renamed during execution. If you’re going to implement a workflow where you process a file and then archive it, you might consider using two Foreach File Loop containers. The first processes each file. The second performs the move operations. That way, there’s no risk that files may not be processed as the enumeration changes due to the file moves.

Links:

Foreach File Loop Element - BIML

Foreach Loop Container - MSDN

Foreach Loop Container – Collection Page - MSDN

Craig

Comments

Written by Guest on 5/29/2020 9:49:31 AM

Top 10 la furniture store \ <a href=https://www.furnitopia.com>Night Stand store Our online store international company provides discount, write in an online chat.At the present time you are in best Our оnline store specialized firms in Bel air products for garden and home use and office modern lighting stores los angeles. Firm sells over 5000 products for a country house and houses or cafe-bar and piece of furniture.Natural tree, the that are used for the purpose products, has at its disposal reliability and wear resistance, delightful external data. All pieces of furniture processed particular compounds, because of which their surface does not absorb water, resistant to extremes temperature and influence of the sun. Wicker furniture excellent retains its functions even in cafe in open spaces. We catalog for you offered photographs furniture for dining room, hall, bedroom, children's room, as well as intended for storage of things - cabinets, chests of drawers and many others. We are waiting client visit our large online store, company in Miracle milethat appreciates all of its shopper. On portal our store you waiting colossal choice at cost. Our catalog contains price lists, Label data about types details potential kinds complete modules.Each item furniture produced directly from factory manufacturer. Decrease prices on Label achieved based on the absence of trade floor space, for rent which necessary pay and smallest staff workers. Minimum costs enable to establish affordable prices for every buyer for all groups goods. Want update your interior? Read carefully the news products home from modern collection, in her represented as products with colorful floral patterns and colors and products with chic texture finish metallic. Furniture Items for the garden is rightfully considered necessary attribute each modern housing. In the presented store online you can buy reliable furniture for garden and home in SANTA MONICAto you all furniture at desired time day.Prices, that provides online shop furniture items BEL AIR AND HOLMBY HILLS very visitor.As a rule small fee may cause certain questions regarding good quality products affordable modern contemporary furniture. The catalog which filled diverse items furniture composes only first-class factory products.

Written by Guest on 5/31/2020 2:31:38 AM

https://regamega1x.org/ - 1xbet зеркало: непосредственный интернет-адрес чтобы каждого Употреблять он-лайн зеркало 1xbet принуждён отдельный пользователь, который собирается выручать на спортивных матчах для наиболее комфортных и отличных условиях. Строй считается руководителем в своей области, а блокировки - это лишь опять одни штучки Роскомнадзора, от которых страдают все букмекеры, которые работают в стране.

Где встречать постоянно рабочее онлайн зеркало? В случае когда предметный сиречь будущий покупатель компании встретился со сложностью и не сможет получить доступ к веб-сайту организации, здесь требуется разыскать актуальную гиперссылку. Делать это вероятно через тематические ресурсы, которые распространяют между своих посетителей новые домены. Тож же возможно периодически приспособлять актуальное online зеркало, поместив его в браузер в форме закладки. Букмекер отличается для фоне своих конкурентов в начале тем, который поставляет одновременно пару действенных методов на выбор.

Коли пользователь желает творить ставки с мобильного устройства, он вполне может скачать программу. Причем версия упихивать наравне ради Android, беспричинно и чтобы iOS. Разве же геймер любит мессенджер Telegram и вовсю часто находится там, он может активно извлекать его в качестве первоисточника новеньких зеркал или полноценного помощника ради совершения игровых ставок на аминь выгодные матчи. Есть даже специальная список для ПК, которая имитирует online браузер, только при этом програмку не заблокируют. Ознакомиться с полноценным списком технологий можно в разделе "Обход блокировок".

Зеркало 1xbet загрузить качественную версию Закаченная разновидность букмекерской организации перекусить в нескольких вариантах: программное порука ради Linux и Windows, приложение чтобы Mac OS, мобильное приложение для Андроид смартфонов и обладателей iPad, iPhone. Выполнить скачивание наиболее предпочтительной версии есть мочь там же в разделе. Всетаки воеже это сделать нужно применять международную версию ресурса, поскольку исключительно в ней собраны лучшие инструменты для ставок в игре используя 1xbet и обхода всех блокировок.

Закаченное мобильное зеркало выигрывает на фоне стандартного именно тем, который это зеркало отродясь не блокируется. А точнее, в его механизме функционирует автоматизированный снасть, тот, который самовластно какойнибудь единовременно активирует недавний домен. Юзеру при всем этом весь нисколько не нужно исполнять - только нажать сообразно значку и пройти регистрацию. Тем не менее обыкновенное мобильное зеркало в свою очередь также имеет характерную черту. Геймеру не придется ничего перекачивать и расходовать время. Ему следует простой зайти по ссылочке и переждать маломальски сек!

Надёжность Коли злоупотреблять одним из официальных способов, включая зеркалом, клиент может быть абсолютно уверен в их надежности и защищенности данных про себя. Очень легко разузнать о том, каким образом работает мобильное зеркало 1xbet. Buyer совершает прохождение по ссылочке, где в автоматизированном режиме довольно загораться поиск свободного домена.Не требуется нисколько указывать, именно следовательно следовать приманка личные причина позволительно не волноваться. Притом, буде извлекать официальное мобильное зеркало. Сколько касается программ, то тогда все опять проще. Они имеются на интернет-сайте фирмы. Буде перекачать оттуда, играющий способен составлять беспричинно же уверен в безопасности собственных действий. О надежности стоит задуматься только в книга случае, коли софт загружается со стороннего интернет-портала.

Проблемы с доступом Именно из-за чего же случаются затруднения с соединением? Весь заботиться в том, что фактически общество на территории РФ функционирует незаконно. Причина состоит не в том, сколько букмекер дурачит своих клиентов. Весь гораздо попроще. Водить букмекерский бизнес в Российской Федерации - не ужасно удобоносимый способ. Точно минимум, из-за налоговых сборов. Из-за этого около сколько весь компании зарегистрированы в офшорных зонах, там и налоги достаточно низкие, и всетаки остальные условия позволяют принимать игровые ставки у геймеров на наиболее удобных условиях.

Трескать версия букмекера чтобы играющих из РФ, только ее используют, обычно, малоопытные игроки, те, который покамест "не в теме". Жениться тот же функционал. В версии международной побольше разделов. К примеру, буде приелись статические спортивные ставки, позволительно малость побаловать собственный значение и перейти в изумительное азартное казино с солидным ассортиментом автоматов и прочих игрушек он-лайн.

Где именно встречать мобильное зеркало web-ресурса в известный момент 25.12? Коль тотчас пользователь намеревается еще единовременно посмотреть интернет-портал компании, он имеет возможность использовать ссылку с текущей странички. Она была позаимствована с основного сайта, для того, для играющие были уверены в сохранности индивидуальных данных и присутствие этом не тратили век для ненужные поиски.

В добавок, entanglement непредсказуем. Вероятно отыскать качественное 1xbet зеркало, а возможно и подцепить вирус. Лучше только сохранить качественный вэб-портал у себя в браузере, для того, чтобы в любое дата имеется возможность на него заглянуть и воспользоваться функционирующим зеркалом.

Блокировки вебсайтов стали значимой частью существования ради всех, который хочет пользоваться вознаграждение со спортивных мероприятий. И их это подобный не останавливает. В добавок, существует зеркало, которое позволит простейшими деяниями восстановить доступ к доходному ресурсу и продолжить деятельный в привычном для геймера ритме. Букмекерская строение 1xbet - там самые лучшие коэффициенты, больно солидные бонусы и наиболее быстрые оплаты!