SQL Server Integration Services (SSIS)

Introduction to SSIS

SQL Server Integration Services (SSIS) is a platform for creating high-performance data integration and workflow automation solutions. This tool enables developers to design data integration and workflow solutions that integrate data from various sources with other business processes, making it perfect for data warehousing, ETL processes, data conversion, data syndication, data migration, and data cleansing tasks. SSIS provides three primary functions:

1. Data Integration: This function of SSIS enables developers to extract data from various sources, including flat files, spreadsheets, or databases, and convert it into the desired format for use in a data warehouse or other business intelligence system. SSIS supports multiple data transformation and migration tasks, including working with Excel spreadsheets, flat files, and other data sources.

2. Workflow Automation: SSIS makes it easy to automate workflows, including ETL scripts, task scheduling, and process monitoring. The package execution workflows allow for conditional branching and looping functionalities.

3. Connectivity and Reliability: With SSIS, you get a highly flexible and scalable connectivity option, which supports not only SQL Server but also other databases including Oracle, Sybase, and Informix.

Developers can create SSIS packages using Visual Studio, Business Intelligence Development Studio (BIDS), or SQL Server Data Tools. Once the package is designed, it can be deployed to the SSIS Catalog, a set of SQL Server databases that maintain a record of packages and their configurations. Developers can also monitor and manage package execution using the SQL Server Management Studio.

SSIS is a powerful tool that enables developers to extract, transform and load (ETL) data in a highly efficient and reliable manner. It provides flexible integration options and supports a wide range of data sources, making it the ideal tool for data warehousing and business intelligence solutions.

Building SSIS Packages

Building SSIS packages involves creating workflows that automate the process of extracting and transforming data from various sources. The process involves a series of practical steps taken to build robust packages. The following are the key steps:

1. Create a new SSIS package: The first step in building a package is to create a new SSIS package using Visual Studio, BIDS, or SQL Server Data Tools. Once you’ve created a package, you can start adding control flow elements, data flow elements, and event handlers to the package.

2. Add control flow elements: Control flow elements define the workflow of the package. These are the elements that manage the execution of the package, such as conditional statements, loops, and task groups.

3. Add data flow elements: Data flow elements define how data is extracted, transformed and loaded (ETL) in the package. These are the elements that move data between sources and destinations, transform data using various transformation types, and clean data before loading it into the target system.

4. Add event handlers: Event handlers are used to add error handling and logging to the package. SSIS provides several event handlers, such as on-preceding task failure, on-error, and on-execution completion.

5. Configure package properties: You can configure package properties, such as connections, variables, and configuration properties, based on the requirements of the package.

6. Debug and test the package: Debugging and testing the package is essential to ensure that it works correctly. SSIS provides robust debugging tools, such as breakpoints, data viewers, and logging.

7. Deploy and execute the package: Once you’ve finished building the package, you can deploy it to the SSIS Catalog and execute it using SQL Server Management Studio.

Building SSIS packages can be complex but following these steps can help the developer build robust and efficient packages that automate data integration and workflows. These packages can be used for various data warehousing and ETL processes, data conversion, and data cleansing tasks.

Control Flow Tasks in SSIS

Control Flow tasks in SSIS are used to create workflows that define how packages execute, including tasks that need to be executed in a predefined sequence, tasks that need to be executed conditionally, and tasks that need to be run in parallel. The following are some of the commonly used Control Flow tasks in SSIS:

1. Execute SQL Task: This is used to execute one or more SQL statements, or a stored procedure, to retrieve or modify data from a database.

2. File System Task: This is used to manage files and directories on the file system using operations like Copy, Move, Delete, and Create.

3. FTP Task: This is used to perform FTP operations, such as downloading and uploading files, on an FTP server.

4. Data Flow Task: This is used for managing data transformations, where data from one source is transformed and loaded to a different destination.

5. Script Task: This is used to perform specific actions using Microsoft Visual Basic .NET or Microsoft Visual C# script code.

6. Send Mail Task: This is used to send an email message to one or more recipients.

The Control Flow tasks are added in the Control Flow tab of the SSIS designer. To add a task, you need to drag and drop the task from the SSIS toolbox onto the designer surface. Once a task is added to a package, the properties of that task can be configured to meet the specific requirements of the package.

Control Flow tasks can be sequenced through precedence constraints that connect the tasks in a workflow. Precedence constraints can be assigned expressions, either logical OR or logical AND to control the flow of the tasks. This means that certain tasks can be set up only to execute after some other tasks have been executed successfully.

In conclusion, Control Flow tasks in SSIS are used to create packages that automate data integration and workflow tasks. By using these tasks, developers can create robust workflows that manage the execution of packages, including conditional and parallel execution of tasks.

Data Flow Tasks in SSIS

Data Flow tasks in SSIS are used for extracting, transforming and loading (ETL) data between sources and destinations. These tasks define how data is read from a source, transformed using different transform types, and finally loaded into a destination. The following are some of the commonly used Data Flow tasks in SSIS:

1. Source task: This is used to extract data from a source system, such as a database or a flat file.

2. Transformation task: This is used to modify data as it moves from the source system to the destination system. Transformations can include a wide range of data operations, such as sorting, merging, aggregating, and merging data.

3. Destination task: This is used to load data into a target system, such as a database table or a flat file.

4. Data Conversion task: This is used to convert data from one data type to another.

5. Lookup task: This is used to match data in one set of data with data in another set of data.

6. Derived Column task: This is used to create new columns based on existing columns in the data flow.

Data Flow tasks are added in the Data Flow tab of the SSIS designer. To add a task, you need to drag and drop the task from the SSIS toolbox onto the designer surface. Once a task is added to a package, the properties of that task can be configured to meet the specific requirements of the package.

Data Flow tasks can be connected in a workflow using data paths. Data paths define the flow of data between the different tasks in the data flow. Data paths can also be assigned conditional expressions to control the flow of data.

In conclusion, Data Flow tasks in SSIS form the core of the ETL process. These tasks are used to extract, transform and load data between sources and destinations. By using these tasks, developers can create robust workflows that manage the entire ETL process, from data extraction to data transformation to data loading.

Summary

SQL Server Integration Services (SSIS) is an essential tool for any data integration and workflow automation. It offers three primary functions such as Data Integration, Workflow Automation, and Connectivity and Reliability. This article covers the basics of SSIS, including its subcomponents, how to build packages, control flow tasks, and data flow tasks. Control Flow tasks manage the package execution and include tasks that need to be executed in a predefined sequence or conditionally or parallel. Data Flow tasks are for extracting, transforming, and loading data between sources and destinations. Using this tool, developers can create robust workflows that automate data integration and workflows.