what is a dts package

SQL Server Data Transformation Services

SQL Server Data Transformation Services (DTS) was a component of Microsoft SQL Server versions 7.0 and 2000. It provided a graphical environment and programming model for creating, managing, and executing packages that extracted, transformed, and loaded data (ETL) between various sources.

Core Functionality

  • Data Extraction: DTS allowed connection to diverse data sources, including relational databases (SQL Server, Oracle, DB2), flat files (CSV, text), and other OLE DB or ODBC compliant sources.
  • Data Transformation: Packages provided a range of transformations to clean, validate, and reshape data. These transformations included data type conversions, string manipulation, lookups, aggregations, and custom scripting capabilities.
  • Data Loading: After transformation, data could be loaded into target data stores, such as SQL Server databases, data warehouses, or flat files.

Package Structure

A DTS package comprised several elements:

  • Connections: Definitions for connecting to data sources and destinations.
  • Tasks: Units of work that performed specific actions, such as executing SQL statements, transferring files, or running transformations.
  • Transformations: Steps to modify data as it flowed between sources and destinations.
  • Workflows: Control flow mechanisms (precedence constraints) to define the order in which tasks and transformations were executed.

Tools and Development Environment

DTS packages were typically developed using the SQL Server Enterprise Manager (SQL Server 7.0) or SQL Server Management Studio (SQL Server 2000). These tools provided a graphical designer for creating and managing packages.

Limitations and Obsolescence

DTS had limitations in scalability, error handling, and version control. It was replaced by SQL Server Integration Services (SSIS), introduced in SQL Server 2005, which provides a more robust and feature-rich ETL platform. DTS packages could be migrated to SSIS in later versions of SQL Server, but this process often required significant rework.

Components and Objects

  • DTS Designer: The graphical interface used to visually construct and configure packages.
  • DTS Object Model: A set of COM objects that allowed programmatic manipulation and execution of packages.
  • Tasks: Pre-built and custom tasks that performed specific operations on data or system resources. Examples include Execute SQL Task, File Transfer Protocol Task, and ActiveX Script Task.
  • Data Transformation Services Packages (DTS Packages): The container holding all connections, tasks, transformations, and workflow logic defining the ETL process.