What is SQL Server

SQL Server Overview

• SQL Server is a RDBMS, a complete database.
• SQL Server is compatible with structured query language and has rich support for XML.
• SQL Server includes number of features that support ease of installation, deployment, scalability, data warehousing and system integration with other server software.

SQL Server Components

• Database engine-It provides support for data access interfaces like ADO, OLEDB and ODBC. Replication-It enables to maintain multiple copies of data on different computers and also keep data well synchronized.
• DTS-It is for importing and transferring data from multiple heterogeneous sources. It is used to build data ware housing and data marts by the process of extracting data from multiple OLTP systems.
• Analysis services-It organizes data from data warehouse cubes to provide rapid answers to complex queries. Analysis the data stored in data warehouse and data marts.
• Meta data services-It is a set of services that helps to manage metadata.

• Metadata describes meaning and description of applications and processes.

SQL Server 2000 Architecture

• SQL Server has Logical Architecture and Physical Architecture.
• The data is organized into logical design that is visible to user.
• Logical components include objects, users, roles, collations, logins and groups.
• The database itself maintains data as files on disk.
• Logical components Objects include table, data type, view, stored procedure, function, index, constraint, rule, default and trigger.
• Collations Control how character strings are stored physically and the rules by which character are stored and compared.
• Logins-Each database user should have login id to allow database to identify.
• Users are who can connect to database.
• Role is a single unit of users having same permission.
• Physical Architecture-Page and extents describes physical database organisation.
• Page is the fundamental unit of data storage. Page is divided into data rows which contain all data.
• Extents is the place where tables and indexes are stored.

Transact SQL

• Allow us to create and manage all objects.
• Client application communicates with SQL server by transact-SQL statement.
• SQL Server supports 3 types of transact-SQL statement namely DDL, DLL and DML