Introduction About SSIS

Introduction About SSIS:

SQL Server Integration Services (SSIS) is a component of the Microsoft SQL Server DB Software which can be used to perform a broad range of data migration tasks.

SSIS is a platform for data integration and workflow applications.It features a fast and flexible data warehousing tool used for data extraction, transformation, and loading (ETL). The tool may also be used to automate maintenance of SQL Server databases and updates to multidimensional cube data.

First released with Microsoft SQL Server 2005, SSIS replaced DTS (Data Transformation Services), which had been a feature of SQL Server since Version 7.0. Unlike DTS, which was included in all versions, SSIS is only available in the "Standard" and "Enterprise" editions.

Features:

The SSIS Import/Export Wizard lets the user create packages that move data from a single data source to a destination with no transformations. The Wizard can quickly move data from a variety of source types to a variety of destination types, including text files and other SQL Server instances.

Developers tasked with creating or maintaining SSIS packages use a visual development tool based on Microsoft Visual Studio called the SQL Server Business Intelligence Development Studio (BIDS).

It allows users to edit SSIS packages using a drag-and-drop user interface. A scripting environment in which to write programming code is also available in the tool. A package holds a variety of elements that define a workflow. Upon package execution, the tool provides color-coded, real-time monitoring.

Connections 

A connection includes the information necessary to connect to a particular data source. Tasks can reference the connection by its name, allowing the details of the connection to be changed or configured at runtime.

Tasks 

A task is an atomic work unit that performs some action. There are a couple of dozen tasks that ship in the box, ranging from the file system task (which can copy or move files) to the data transformation task. The data transformation task actually copies data; it implements the ETL features of the product.

Precedence constraints 

Tasks are linked by precedence constraints. The precedence constraint preceding a particular task must be met before that task executes. The runtime supports executing tasks in parallel if their precedence constraints so allow. Constraints may otherwise allow different paths of execution depending on the success or failure of other tasks. Together with the tasks, precedence constraints comprise the workflow of the package.

Event handlers 

A workflow can be designed for a number of events in the different scopes where they might occur. In this way, tasks may be executed in response to happenings within the package —such as cleaning up after errors.

Variables 

Tasks may reference variables to store results, make decisions, or affect their configuration.

- A package may be saved to a file or to a store with a hierarchical namespace within a SQL Server instance. In either case, the package content is persisted in XML.

- Once completed, the designer also allows the user to start the package's execution. Once started, the package may be readily debugged or monitored.

Features of the data flow task

SSIS provides the following built-in transformations:

• Conditional Split
• Multicast
• Union-All, Merge, and Merge Join
• Sort
• Fuzzy Grouping
• Lookup and Fuzzy Lookup
• Percentage Sampling and Row Sampling
• Copy/Map, Data Conversion, and Derived Column
• Aggregation
• Data Mining Model Training, Data Mining Query, Partition Processing, and Dimension Processing
• Pivot and
• Slowly Changing Dimension
• Script Component

The Conditional Split transformation is used to speed up the query on the source table based on a particular condition. It is similar to the "if..else" construct in the C language.

Other included tools

Aside from the Import/Export Wizard and the designer, the product includes a few other notable tools.

DTEXEC executes a package from the command line wherever it may be stored. Before running the package, the tool may be instructed to apply configuration information, which will allow the same package to be reused with slightly different parameters, including different connection strings for its endpoints.

DTUTIL provides the ability to manage packages, again from the Command Prompt. The tool can copy or move a package from a file into the server store, or back out again. Among a few other sundry functions, it can be used to delete, rename, encrypt, or decrypt packages.

Extensibility and programmability

Users may write code to define their own connection objects, log providers, transforms, and tasks.

SSIS features a programmable object model that allows developers to write their own hosts for package execution. Such a host can respond to events, start and stop packages, and so on. The object model also allows developers to create, store, and load packages, as well as create, destroy, and modify any of the contained objects.

It can be used on all versions of SQL Server 2005 except Express and Workgroup.