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SQL

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SQL Meaning

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SQL (Structured Query Language)is a specialized programming language designed for managing and manipulating data stored in relational databases. It allows users to perform various operations such as querying, updating, inserting, and deleting data efficiently12.

Key Principles of SQL

  1. Declarative Language: SQL is a declarative language, meaning it specifies what data to retrieve or manipulate rather than how to perform the operation. This makes it easier to use and understand1.

  2. Standardization: SQL became a standard of the American National Standards Institute (ANSI) in 1986 and the International Organization for Standardization (ISO) in 19872.

  3. Components: SQL consists of several sublanguages, including Data Query Language (DQL), Data Definition Language (DDL), Data Control Language (DCL), and Data Manipulation Language (DML)1.

Common SQL Commands

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  • SELECT: Retrieves data from a database.

  • INSERT: Adds new records to a database.

  • UPDATE: Modifies existing records.

  • DELETE: Removes records from a database.

  • CREATE: Creates new database objects like tables and views.

  • ALTER: Modifies existing database objects.

  • DROP: Deletes database objects23.

Example of a Simple SQL Query

SELECT*FROMCustomersWHERECustomerNameLIKE'J%'ORDER BYCustomerIDDESCLIMIT 10;

This query retrieves the top 10 customers whose names start with 'J', ordered in descending order by their customer ID3.

Uses of SQL

SQL is widely used across various industries and applications, including:

  • Data Retrieval: Extracting data from databases for analysis and reporting.

  • Data Manipulation: Adding, updating, and deleting data in databases.

  • Data Definition: Defining the structure and organization of data in databases.

  • Access Control: Managing user permissions and ensuring data security23.

Important Considerations

  • Interoperability: SQL implementations can vary between different database systems, leading to compatibility issues1.

  • Security: SQL injection is a common security vulnerability where malicious SQL code is inserted into queries to manipulate or corrupt data3.

In conclusion, SQL is a powerful and versatile language for managing relational databases, offering a wide range of functionalities for data manipulation, retrieval, and security12.

​Market Harborough is a market town within the Harborough district of Leicestershire, England. It is situated in the far southeast of the county, forming part of the border with Northamptonshire.

Harborough District has a population of 91,461 (2017)[1] and Market Harborough is the district's administrative headquarters.[2] It sits on the Northamptonshire-Leicestershire border. The town was formerly at a crossroads for both road and rail; however the A6 now bypasses the town to the east and the A14 which carries east-west traffic is 6 miles (9.7 km) to the south. Market Harborough railway station is served by East Midlands Railway services on the Midland Main Line with direct services north to Leicester, Nottingham, Derby and Sheffield and south to London St Pancras. Rail services to Rugby and Peterborough ended in 1966.

Market Harborough is located in an area which was formerly a part of the Rockingham Forest, a royal hunting forest used by the medieval monarchs starting with William I. Rockingham Road takes its name from the forest. The forest's original boundaries stretched from Market Harborough through to Stamford and included the settlements at Corby, Kettering, Desborough, Rothwell, Thrapston and Oundle.

The steeple of St Dionysius' Church rises directly from the street, as there is no churchyard. It was constructed in grey stone in 1300 with the church itself a later building of about 1470. Next to the church stands the Old Grammar School, a small timber building dating from 1614. The ground floor is open, creating a covered market area and there is a single room on the first floor. It has become a symbol of the town. The nearby square is largely pedestrianised and surrounded by buildings of varying styles. The upper end of the High Street is wide and contains mostly unspoiled Georgian buildings.

Market Harborough has two villages within its confines: Great Bowden lies over a hill about a mile from the town centre; Little Bowden is less than half a mile from the town centre. The three centres have largely coalesced through ribbon development and infill, although Great Bowden continues to retain a strong village identity.