Sql Introduction to Database
Oracle’s database language Is SQL, which Is used for storing and retrieving Information. SQL allows users to access data In elation database management systems, such as Oracle, Sybase, Inform, Microsoft SQL Server, Access, and others, by allowing users to describe the data the user wishes to see. A table is a primary database object of SQL that is used to store data. A table holds data in the form of rows and columns Characteristics of SQL SQL is an ANSI and ISO standard computer language for creating and manipulating databases. SQL allows the user to create, update, delete, and retrieve data from a database.
SQL Is very simple and easy to learn. SQL works with database programs like DUB, Oracle, MS Access, Sybase, MS SQL Sever etc. Advantages of SQL: High Speed: SQL Queries can retrieve large amounts of records from a database quickly and efficiently. Well Defined Standards Exist: SQL databases use long- established standard,which is being adopted by ANSI : ISO. Non-SQL databases do not adhere to any clear standard. No Coding Required: using standard SQL it is easier to manage database systems without having to write substantial amount of code.
Emergence of ORDERS: Previously SQL databases were synonymous with relational database. With the emergence of Object Oriented DB’S, object storage capabilities are extended to relational databases. Disadvantages of SQL: Difficulty in Interfacing: Interfacing an SQL database is more complex than adding a few lines of code. More Features Implemented in Proprietary way: Although SQL databases conform to ANSI & ISO standards, some databases go for proprietary extensions to standard SQL to ensure vendor lock-Len. Language elements which are in some cases optional, constituent components of statements and queries.
Expressions which can produce either scalar values or tables consisting of columns and rows of data. ; Predicates which specify conditions that can be evaluated to SQL three-valued logic (EVIL) Boolean truth values and which are used to emit the effects of statements and queries, or to change program flow. Queries which retrieve data based on specific criteria. Statements which may have a persistent effect on schemas and data, or which may control transactions, program flow, connections, sessions, or diagnostics. SQL statements also include the semicolon (“;”) statement terminator.
Though not required on every platform, it is defined as a standard part of the SQL grammar. Insignificant whiteface is generally ignored in SQL statements and queries, making it easier to format SQL code for readability.