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Implement a Lookup Transformation in Full Cache Mode Using the Cache Connection Manager

You can configure the Lookup transformation to use full cache mode and a Cache connection manager. In full cache mode, the reference dataset is loaded into cache before the Lookup transformation runs.

Note Note

The Cache connection manager does not support the Binary Large Object (BLOB) data types DT_TEXT, DT_NTEXT, and DT_IMAGE. If the reference dataset contains a BLOB data type, the component will fail when you run the package. You can use the Cache Connection Manager Editor to modify column data types. For more information, see Cache Connection Manager Editor.

The Lookup transformation performs lookups by joining data in input columns from a connected data source with columns in a reference dataset. For more information, see Lookup Transformation.

You use one of the following to generate a reference dataset:

  • Cache file (.caw)

    You configure the Cache connection manager to read data from an existing cache file.

  • Connected data source in the data flow

    You use a Cache Transform transformation to write data from a connected data source in the data flow to a Cache connection manager. The data is always stored in memory.

    You must add the Lookup transformation to a separate data flow. This enables the Cache Transform to populate the Cache connection manager before the Lookup transformation is executed. The data flows can be in the same package or in two separate packages.

    If the data flows are in the same package, use a precedence constraint to connect the data flows. This enables the Cache Transform to run before the Lookup transformation runs.

    If the data flows are in separate packages, you can use the Execute Package task to call the child package from the parent package. You can call multiple child packages by adding multiple Execute Package tasks to a Sequence Container task in the parent package.

You can share the reference dataset stored in cache, between multiple Lookup transformations by using one of the following methods:

  • Configure the Lookup transformations in a single package to use the same Cache connection manager.

  • Configure the Cache connection managers in different packages to use the same cache file.

For more information, see the following topics:

For a video that demonstrates how to implement a Lookup transformation in Full Cache mode using the Cache connection manager, see How to: Implement a Lookup Transformation in Full Cache Mode (SQL Server Video).

To implement a Lookup transformation in full cache mode in one package by using Cache connection manager and a data source in the data flow

  1. In SQL Server Data Tools (SSDT), open a Integration Services project, and then open a package.

  2. On the Control Flow tab, add two Data Flow tasks, and then connect the tasks by using a green connector:

  3. In the first data flow, add a Cache Transform transformation, and then connect the transformation to a data source.

    Configure the data source as needed.

  4. Double-click the Cache Transform, and then in the Cache Transformation Editor, on the Connection Manager page, click New to create a new Cache connection manager.

  5. Click the Columns tab of the Cache Connection Manager Editor dialog box, and then specify which columns are the index columns by using the Index Position option.

    For non-index columns, the index position is 0. For index columns, the index position is a sequential, positive number.

    Note Note

    When the Lookup transformation is configured to use a Cache connection manager, only index columns in the reference dataset can be mapped to input columns. Also, all index columns must be mapped. For more information, see Cache Connection Manager Editor.

  6. To save the cache to a file, in the Cache Connection Manager Editor, on the General tab, configure the Cache connection manager by setting the following options:

    • Select Use file cache.

    • For File name, either type the file path or click Browse to select the file.

      If you type a path for a file that does not exist, the system creates the file when you run the package.

    Note Note

    The protection level of the package does not apply to the cache file. If the cache file contains sensitive information, use an access control list (ACL) to restrict access to the location or folder in which you store the file. You should enable access only to certain accounts. For more information, see Access to Files Used by Packages.

  7. Configure the Cache Transform as needed. For more information, see Cache Transformation Editor (Connection Manager Page) and Cache Transformation Editor (Mappings Page).

  8. In the second data flow, add a Lookup transformation, and then configure the transformation by doing the following tasks:

    1. Connect the Lookup transformation to the data flow by dragging a connector from a source or a previous transformation to the Lookup transformation.

      Note Note

      A Lookup transformation might not validate if that transformation connects to a flat file that contains an empty date field. Whether the transformation validates depends on whether the connection manager for the flat file has been configured to retain null values. To ensure that the Lookup transformation validates, in the Flat File Source Editor, on the Connection Manager Page, select the Retain null values from the source as null values in the data flow option.

    2. Double-click the source or previous transformation to configure the component.

    3. Double-click the Lookup transformation, and then in the Lookup Transformation Editor, on the General page, select Full cache.

    4. In the Connection type area, select Cache connection manager.

    5. From the Specify how to handle rows with no matching entries list, select an error handling option.

    6. On the Connection page, from the Cache connection manager list, select a Cache connection manager.

    7. Click the Columns page, and then drag at least one column from the Available Input Columns list to a column in the Available Lookup Column list.

      Note Note

      The Lookup transformation automatically maps columns that have the same name and the same data type.

      Note Note

      Columns must have matching data types to be mapped. For more information, see Integration Services Data Types.

    8. In the Available Lookup Columns list, select columns. Then in the Lookup Operation list, specify whether the values from the lookup columns replace values in the input column or are written to a new column.

    9. To configure the error output, click the Error Output page and set the error handling options. For more information, see Lookup Transformation Editor (Error Output Page).

    10. Click OK to save your changes to the Lookup transformation.

  9. Run the package.

To implement a Lookup transformation in full cache mode in two packages by using Cache connection manager and a data source in the data flow

  1. In SQL Server Data Tools (SSDT), open a Integration Services project, and then open two packages.

  2. On the Control Flow tab in each package, add a Data Flow task.

  3. In the parent package, add a Cache Transform transformation to the data flow, and then connect the transformation to a data source.

    Configure the data source as needed.

  4. Double-click the Cache Transform, and then in the Cache Transformation Editor, on the Connection Manager page, click New to create a new Cache connection manager.

  5. In the Cache Connection Manager Editor, on the General tab, configure the Cache connection manager by setting the following options:

    • Select Use file cache.

    • For File name, either type the file path or click Browse to select the file.

      If you type a path for a file that does not exist, the system creates the file when you run the package.

    Note Note

    The protection level of the package does not apply to the cache file. If the cache file contains sensitive information, use an access control list (ACL) to restrict access to the location or folder in which you store the file. You should enable access only to certain accounts. For more information, see Access to Files Used by Packages.

  6. Click the Columns tab, and then specify which columns are the index columns by using the Index Position option.

    For non-index columns, the index position is 0. For index columns, the index position is a sequential, positive number.

    Note Note

    When the Lookup transformation is configured to use a Cache connection manager, only index columns in the reference dataset can be mapped to input columns. Also, all index columns must be mapped. For more information, see Cache Connection Manager Editor.

  7. Configure the Cache Transform as needed. For more information, see Cache Transformation Editor (Connection Manager Page) and Cache Transformation Editor (Mappings Page).

  8. Do one of the following to populate the Cache connection manager that is used in the second package:

    • Run the parent package.

    • Double-click the Cache connection manager you created in step 4, click Columns, select the rows, and then press CTRL+C to copy the column metadata.

  9. In the child package, create a Cache connection manager by right-clicking in the Connection Managers area, clicking New Connection, selecting CACHE in the Add SSIS Connection Manager dialog box, and then clicking Add.

    The Connection Managers area appears on the bottom of the Control Flow, Data Flow, and Event Handlers tabs of Integration Services Designer.

  10. In the Cache Connection Manager Editor, on the General tab, configure the Cache connection manager to read the data from the cache file that you selected by setting the following options:

    • Select Use file cache.

    • For File name, either type the file path or click Browse to select the file.

    Note Note

    The protection level of the package does not apply to the cache file. If the cache file contains sensitive information, use an access control list (ACL) to restrict access to the location or folder in which you store the file. You should enable access only to certain accounts. For more information, see Access to Files Used by Packages.

  11. If you copied the column metadata in step 8, click Columns, select the empty row, and then press CTRL+V to paste the column metadata.

  12. Add a Lookup transformation, and then configure the transformation by doing the following:

    1. Connect the Lookup transformation to the data flow by dragging a connector from a source or a previous transformation to the Lookup transformation.

      Note Note

      A Lookup transformation might not validate if that transformation connects to a flat file that contains an empty date field. Whether the transformation validates depends on whether the connection manager for the flat file has been configured to retain null values. To ensure that the Lookup transformation validates, in the Flat File Source Editor, on the Connection Manager Page, select the Retain null values from the source as null values in the data flow option.

    2. Double-click the source or previous transformation to configure the component.

    3. Double-click the Lookup transformation, and then select Full cache on the General page of the Lookup Transformation Editor.

    4. Select Cache connection manager in the Connection type area.

    5. Select an error handling option for rows without matching entries from the Specify how to handle rows with no matching entries list.

    6. On the Connection page, from the Cache connection manager list, select the Cache connection manager that you added.

    7. Click the Columns page, and then drag at least one column from the Available Input Columns list to a column in the Available Lookup Column list.

      Note Note

      The Lookup transformation automatically maps columns that have the same name and the same data type.

      Note Note

      Columns must have matching data types to be mapped. For more information, see Integration Services Data Types.

    8. In the Available Lookup Columns list, select columns. Then in the Lookup Operation list, specify whether the values from the lookup columns replace values in the input column or are written to a new column.

    9. To configure the error output, click the Error Output page and set the error handling options. For more information, see Lookup Transformation Editor (Error Output Page).

    10. Click OK to save your changes to the Lookup transformation.

  13. Open the parent package, add an Execute Package task to the control flow, and then configure the task to call the child package. For more information, see Execute Package Task.

  14. Run the packages.

To implement a Lookup transformation in full cache mode by using Cache connection manager and an existing cache file

  1. In SQL Server Data Tools (SSDT), open a Integration Services project, and then open a package.

  2. Right-click in the Connection Managers area, and then click New Connection.

    The Connection Managers area appears on the bottom of the Control Flow, Data Flow, and Event Handlers tabs of Integration Services Designer.

  3. In the Add SSIS Connection Manager dialog box, select CACHE, and then click Add to add a Cache connection manager.

  4. Double-click the Cache connection manager to open the Cache Connection Manager Editor.

  5. In the Cache Connection Manager Editor, on the General tab, configure the Cache connection manager by setting the following options:

    • Select Use file cache.

    • For File name, either type the file path or click Browse to select the file.

    Note Note

    The protection level of the package does not apply to the cache file. If the cache file contains sensitive information, use an access control list (ACL) to restrict access to the location or folder in which you store the file. You should enable access only to certain accounts. For more information, see Access to Files Used by Packages.

  6. Click the Columns tab, and then specify which columns are the index columns by using the Index Position option.

    For non-index columns, the index position is 0. For index columns, the index position is a sequential, positive number.

    Note Note

    When the Lookup transformation is configured to use a Cache connection manager, only index columns in the reference dataset can be mapped to input columns. Also, all index columns must be mapped. For more information, see Cache Connection Manager Editor.

  7. On the Control Flow tab, add a Data Flow task to the package, and then add a Lookup transformation to the data flow.

  8. Configure the Lookup transformation by doing the following:

    1. Connect the Lookup transformation to the data flow by dragging a connector from a source or a previous transformation to the Lookup transformation.

      Note Note

      A Lookup transformation might not validate if that transformation connects to a flat file that contains an empty date field. Whether the transformation validates depends on whether the connection manager for the flat file has been configured to retain null values. To ensure that the Lookup transformation validates, in the Flat File Source Editor, on the Connection Manager Page, select the Retain null values from the source as null values in the data flow option.

    2. Double-click the source or previous transformation to configure the component.

    3. Double-click the Lookup transformation, and then in the Lookup Transformation Editor, on the General page, select Full cache.

    4. Select Cache connection manager in the Connection type area.

    5. Select an error handling option for rows without matching entries from the Specify how to handle rows with no matching entries list.

    6. On the Connection page, from the Cache connection manager list, select the Cache connection manager that you added.

    7. Click the Columns page, and then drag at least one column from the Available Input Columns list to a column in the Available Lookup Column list.

      Note Note

      The Lookup transformation automatically maps columns that have the same name and the same data type.

      Note Note

      Columns must have matching data types to be mapped. For more information, see Integration Services Data Types.

    8. In the Available Lookup Columns list, select columns. Then in the Lookup Operation list, specify whether the values from the lookup columns replace values in the input column or are written to a new column.

    9. To configure the error output, click the Error Output page and set the error handling options. For more information, see Lookup Transformation Editor (Error Output Page).

    10. Click OK to save your changes to the Lookup transformation.

  9. Run the package.

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