SQL (Structured Query Language)

SQL allows users to access data in relational database management systems, such as Oracle, Sybase, Informix, Microsoft SQL Server, Access, and others, by allowing users to describe the data the user wishes to see. SQL also allows users to define the data in a database, and manipulate that data.

SQL is an international standard (and ANSI) for definition and manipulation of databases. Almost all database vendors support SQL while adding their own SQL extensions. Originally developed by IBM as a result of the work on the relational model, it was first made commercial by Relational Systems, now called Oracle Corporation in late 1970s.

SQL has been created such that it is intuitive, simple, non-procedural and maps human’s cognitive model. Ideally, programmers and business users need not know how or where data is stored. They should be able to specify what they want and how they want given their requirements. The main objectives of SQL are:

Define database such as tables, attributes, data type, relational keys (primary key, foreign key, referential integrity constraints), domain constraints and indexes.

Defining data access controls on tables (and other database objects) through Grants, Views.

Altering, dropping, and replacing the above

Inserting, updating, and deleting data in the tables

Performing queries that involve table joins, various types of conditions and nested-queries (i.e., queries within queries).

SQL Server 2008

SQL Server 2008 is Microsoft’s enterprise-class database server, designed to compete with products such as Oracle and IBM’s DB2. SQL Server allows you to store, retrieve, and manipulate data to meet your organization’s business objectives. The platform provides a number of tools and technologies to assist you in managing and manipulating your data on your own terms. For example, using SQL Server 2008, you can

Import and export data from a variety of file formats

Link to other databases (both SQL Server and those of other manufacturers)
Manipulate data from within Microsoft Excel and Microsoft Access
Produce professional-quality dynamic reports based on SQL Server data
Create automated tasks that trigger when data satisfies specified conditions

The Declarative Management Framework (DMF) is one of the most revolutionary features in SQL Server 2008. DMF allows database administrators to set high-level policies describing the allowed configuration status of DMF managed SQL Server instances. DMF allows administrators to

Create policies governing SQL Server configurations
Evaluate an instance’s current configuration against a policy and determine what deficiencies, if any, exist
Apply a policy to a SQL Server instance
Log or prevent any changes to a SQL Server instance that would bring it out of compliance with policy

Date and time data types that match the way normal people think about dates and times! SQL Server 2008 provides four new data types that answer this formerly unmet demand:

The DATE data type is a calendar date only, with no time information.
The TIME data type is a time only, with no date information.
The DATETIMEOFFSET data type is a date/time that allows for the inclusion of time zone information.
The DATETIME2 data type allows the specification of a date anywhere within the range of the year 1 A.D. to the year 9999 A.D

The highlights of the initial CTP (Community Technology Preview) release include the following features:

SQL Server Integration Services (SSIS) – the script task and script component now support development in C# and full debugging capabilities.
SQL Server Analysis Services (SSAS) –the user interface for creating and editing dimensions is enhanced to guide users toward designs that follow best practices.
Star Join Query Optimization – improved query performance by recognizing common data warehousing join patterns.
MERGE SQL Statement – added support for the MERGE SQL statement which is especially useful in data warehousing where data is inserted if it does not exist or updated if it does exist. MERGE is a single statement that handles both conditions.

Change Data Capture – a generic component that tracks database changes asynchronously and exposes the changes through a relational interface. This is another big enhancement in the data warehousing area where data changes need to be captured and used to update dimensions.
Table Value Parameters – provides an easier way to define a table type as well as allow applications to create, populate and pass table structured parameters to stored procedures and functions.
Declarative Management Framework – a policy-based mechanism to ensure compliance with policies for system configuration and to prevent or monitor changes.