Overview of Database Concepts
A database is a structured collection of records of data. Its group os objects.
The first database management systems were developed in the 1960s. A pioneer in the field was Charles Bachman
First it was in the form of Files.
Later created like Foxpro, Dbase.
The relational model was proposed by E. F. Codd in 1970.
The rules
Rule 0: The system must qualify as relational, as a database, and as a management system.
For a system to qualify as a relational database management system (RDBMS), that system must use its relational facilities (exclusively) to manage the database.
Rule 1: The information rule:
All information in the database is to be represented in one and only one way, namely by values in column positions within rows of tables.
Rule 2: The guaranteed access rule:
All data must be accessible with no ambiguity. This rule is essentially a restatement of the fundamental requirement for primary keys. It says that every individual scalar value in the database must be logically addressable by specifying the name of the containing table, the name of the containing column and the primary key value of the containing row.
Rule 3: Systematic treatment of null values:
The DBMS must allow each field to remain null (or empty). Specifically, it must support a representation of "missing information and inapplicable information" that is systematic, distinct from all regular values (for example, "distinct from zero or any other number," in the case of numeric values), and independent of data type. It is also implied that such representations must be manipulated by the DBMS in a systematic way.
Rule 4: Active online catalog based on the relational model:
The system must support an online, inline, relational catalog that is accessible to authorized users by means of their regular query language. That is, users must be able to access the database's structure (catalog) using the same query language that they use to access the database's data.
Rule 5: The comprehensive data sublanguage rule:
The system must support at least one relational language that
(a) Has a linear syntax
(b) Can be used both interactively and within application programs,
(c) Supports data definition operations (including view definitions), data manipulation operations (update as well as retrieval), security and integrity constraints, and transaction management operations (begin, commit, and rollback).
Rule 6: The view updating rule:
All views that are theoretically updatable must be updatable by the system.
Rule 7: High-level insert, update, and delete:
The system must support set-at-a-time insert, update, and delete operators. This means that data can be retrieved from a relational database in sets constructed of data from multiple rows and/or multiple tables. This rule states that insert, update, and delete operations should be supported for any retrievable set rather than just for a single row in a single table.
Rule 8: Physical data independence:
Changes to the physical level (how the data is stored, whether in arrays or linked lists etc.) must not require a change to an application based on the structure.
Rule 9: Logical data independence:
Changes to the logical level (tables, columns, rows, and so on) must not require a change to an application based on the structure. Logical data independence is more difficult to achieve than physical data independence.
Rule 10: Integrity independence:
Integrity constraints must be specified separately from application programs and stored in the catalog. It must be possible to change such constraints as and when appropriate without unnecessarily affecting existing applications.
Rule 11: Distribution independence:
The distribution of portions of the database to various locations should be invisible to users of the database. Existing applications should continue to operate successfully :
(a) when a distributed version of the DBMS is first introduced; and
(b) when existing distributed data are redistributed around the system.
Rule 12: The nonsubversion rule:
If the system provides a low-level (record-at-a-time) interface, then that interface cannot be used to subvert the system, for example, bypassing a relational security or integrity constraint.
During the 1980s, research activity focused on distributed database systems and database machines.
In the 1990s, attention shifted to object-oriented databases. These had some success in fields where it was necessary to handle more complex data than relational systems could easily cope with, such as spatial databases, engineering data (including software repositories), and multimedia data.
In the 2000s, the fashionable area for innovation is the XML database. As with object databases, this has spawned a new collection of start-up companies, but at the same time the key ideas are being integrated into the established relational products.
Some of DBMS Products :
ADABAS
BerkeleyDB
dBase
IBM DB2
Informix
Microsoft Access
Microsoft SQL Server
MySQL
Oracle Database
Paradox (database)
Sybase
Teradata
MS SQL SERVER
Microsoft SQL Server is a relational database management system (RDBMS) produced by Microsoft. Its primary query language is Transact-SQL, an implementation of the ANSI/ISO standard Structured Query Language (SQL) used by both Microsoft and Sybase.
For each databse query languge will use :
Oracle : PL/SQL
Sqlserver : T-Sql
Architecture
The architecture of Microsoft SQL Server is broadly divided into three components: SQLOS which implements the basic services required by SQL Server, including thread scheduling, memory management and I/O management; the Relational Engine, which implements the relational database components including support for databases, tables, queries and stored procedures as well as implementing the type system; and the Protocol Layer which exposes the SQL Server functionality.[1]
SQLOS
SQLOS is the base component in the SQL Server architecture. It implements functions normally associated with the Operating System - thread scheduling, memory management, I/O management, buffer pool management, resource management, synchronization primitives and locking, and deadlock detection.
Relational engine
The Relational engine implements the relational data store using the capabilities provided by SQLOS, which is exposed to this layer via the private SQLOS API.
Protocol layer
Protocol layer implements the external interface to SQL Server.
SQL Server 2005
SQL Server 2005, released in November 2005, is the successor to SQL Server 2000. It included native support for managing XML data, in addition to relational data.
SQL Server 2008
The next version of SQL Server is SQL Server 2008,[29] code-named "Katmai",[30] slated to launch on February 27, 2008 and release (RTM) in Q3 2008.[31][32] The most recent CTP was made available on February 19, 2008. SQL Server 2008 aims[33] to make data management self-tuning, self organizing, and self maintaining with the development of SQL Server Always On technologies, to provide near-zero downtime. SQL Server 2008 will also include support for structured and semi-structured data, including digital media formats for pictures, audio, video and other multimedia data. In current versions, such multimedia data can be stored as BLOBs (binary large objects), but they are generic bitstreams. Intrinsic awareness of multimedia data will allow specialized functions to be performed on them. According to Paul Flessner, senior Vice President, Server Applications, Microsoft Corp., SQL Server 2008 can be a data storage backend for different varieties of data: XML, email, time/calendar, file, document, spatial, etc as well as perform search, query, analysis, sharing, and synchronization across all data types.[30]
Tools
SQLCMD
SQLCMD is a command line application that comes with Microsoft SQL Server, and exposes the management features of SQL Server. It allows SQL queries to be written and executed from the command prompt.
Visual Studio
Microsoft Visual Studio includes native support for data programming with Microsoft SQL Server. It can be used to write and debug code to be executed by SQL CLR.
SQL Server Management Studio is a GUI tool included with SQL Server 2005 and later for configuring, managing, and administering all components within Microsoft SQL Server.
Business Intelligence Development Studio
Business Intelligence Development Studio (BIDS) is the IDE from Microsoft used for developing data analysis and Business Intelligence solutions utilizing the Microsoft SQL Server Analysis Services, Reporting Services and Integration Services.
SQL Server Release HistoryVersion Year Release Name Codename
1.0 1989 SQL Server 1.0 -
4.21 1993 SQL Server
6.0 1995 SQL Server
6.5 1996 SQL Server 6.5 Hydra
7.0 1998 SQL Server 7.0 Sphinx-
1999 SQL Server 7.0
OLAP Tools
8.0 2000 SQL Server 2000 Shiloh
8.0 2003 SQL Server 2000 64-bit Edition Liberty
9.0 2005 SQL Server 2005 Yukon
10.0 2008 SQL Server 2008 Katmai
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