Execute Package Task
The Execute Package task extends the enterprise capabilities of Integration Services by letting packages run other packages as part of a workflow.
You can use the Execute Package task for the following purposes:
- Breaking down complex package workflow. This task lets you break down workflow into multiple packages, which are easier to read, test, and maintain. For example, if you are loading data into a star schema, you can build a separate package to populate each dimension and the fact table.
- Reusing parts of packages. Other packages can reuse parts of a package workflow. For example, you can build a data extraction module that can be called from different packages. Each package that calls the extraction module can perform different data scrubbing, filtering, or aggregation operations.
- Grouping work units. Units of work can be encapsulated into separate packages and joined as transactional components to the workflow of a parent package. For example, the parent package runs the accessory packages, and based on the success or failure of the accessory packages, the parent package either commits or rolls back the transaction.
- Controlling package security. Package authors require access to only a part of a multipackage solution. By separating a package into multiple packages, you can provide a greater level of security, because you can grant an author access to only the relevant packages.
A package that runs other packages is generally referred to as the parent package, and the packages that a parent workflow runs are called child packages.
The Execute Package task can run packages stored in the SQL Server msdb database and packages stored in the file system. The task uses an OLE DB connection manager to connect to SQL Server and a File connection manager to access the file system. For more information, see OLE DB Connection Manager and Flat File Connection Manager.
The Execute Package task can also run a database maintenance plan, which lets you manage both SSIS packages and database maintenance plans in the same Integration Services solution. A database maintenance plan is similar to an SSIS package, but a plan can include only database maintenance tasks, and it is always stored in msdb. For more information, see Maintaining Databases (Database Engine) and Maintenance Tasks.
If you choose a package stored in the file system, you must provide the name and location of the package. The package can reside anywhere in the file system; it does not have to be in the same folder as the parent package.
The child package can be run in the process of the parent package, or it can be run in its own process. Running the child package in its own process requires more memory, but it provides more flexibility. For example, if the child process fails, the parent process can continue to run.
Alternatively, sometimes you want the parent and child packages to fail together as one unit, or you might not want to incur the additional overhead of another process. For example, if a child process fails and subsequent processing in the parent process of the package depends on success of the child process, the child package should run in the process of the parent package.
By default, the ExecuteOutOfProcess property of the Execute Package task is set to False, and the child package runs in the same process as the parent package. If you set this property to True, you can debug only packages that contain limited functionality. To debug all packages supported by your edition of SQL Server 2005, you must install Integration Services.
Extending Transactions
The transaction that the parent package uses can extend to the child package; therefore, the work both packages perform can be committed or rolled back. For example, the database inserts that the parent package performs can be committed or rolled back, depending on the database inserts that the child package performs, and vice versa. For more information, see Inherited Transactions.
Propagating Logging Details
The child package that the Execute Package task runs may or may not be configured to use logging, but the child package will always forward the log details to the parent package. If the Execute Package task is configured to use logging, the task logs the log details from the child package. For more information, see Implementing Logging in Packages.
Passing Values to Child Packages
Frequently a child package uses values passed to it by another package that calls it, ordinarily its parent package. Using values from a parent package is useful in scenarios such as the following:
- Parts of a larger workflow are assigned to different packages. For example, one package downloads data on a nightly basis, summarizes the data, assigns summary data values to variables, and then passes the values to another package for additional processing of the data.
- The parent package dynamically coordinates tasks in a child package. For example, the parent package determines the number of days in a current month and assigns the number to a variable, and the child package performs a task that number of times.
- A child package requires access to data that is dynamically derived by the parent package. For example, the parent package extracts data from a table and loads the rowset into a variable, and the child package performs additional operations on the data.
You can use package configurations to make values from the parent package available to the child package. Integration Services provides a configuration type, the Parent Package Variable configuration, for passing values from parent to child packages. The configuration is built on the child package and uses a variable in the parent package.
The parent package variable can be defined in the scope of the Execute Package task or in a parent container such as the package. If multiple variables with the same name are available, the variable defined in the scope of the Execute Package task is used, or the variable that is closest in scope to the task. The configuration is then mapped to a variable in the child package, or to the property of an object in the child package. The variable can also be used in the scripts used by the ActiveX Script task, Script task, or Script component.
For more information, see How to: Use Values of Parent Variables in Child Packages.
Other Related Tasks
Integration Services includes tasks that perform workflow operations, such as executing SQL Server 2000 packages, executables, and batch files.
For more information about these tasks, click one of the following topics:
Configuring the Execute Package Task
You can set properties through SSIS Designer or programmatically.
For more information about the properties that you can set in SSIS Designer, click one of the following topics:
- Execute Package Task Editor (General Page)
- Execute Package Task Editor (Package Page)
- Expressions Page
For more information about how to set these properties in SSIS Designer, click the following topic:
Configuring the Execute Package Task Programmatically
For more information about programmatically setting these properties, click the following topic:
See Also
Concepts
Integration Services Tasks
Creating Package Control Flow
Help and Information
Getting SQL Server 2005 Assistance
Change History
| Release | History |
|---|---|
5 December 2005 |
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