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SQL
SQL Meaning
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
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.
Standardization: SQL became a standard of the American National Standards Institute (ANSI) in 1986 and the International Organization for Standardization (ISO) in 19872.
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
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.
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.
Braintree is a town in Essex, England, and is the principal settlement of Braintree District. It is located 10 miles (16 km) north-east of Chelmsford, 15 miles (24 km) west of Colchester and 35 miles (56 km) north-west of Southend-on-Sea. According to the 2021 Census, the town had a population of 43,492; the urban area, which includes Great Notley, Rayne, Tye Green and High Garrett, had a population of 55,793.[1]
Braintree district has four market towns, picturesque villages, a designer shopping outlet, historic houses and gardens.
The town has grown contiguously with several surrounding settlements. The original settlement and parish of Braintree lay on the River Brain and was bounded on the north by Stane Street, the Roman road from Braughing to Colchester. North of that road was the parish of Bocking. The two parishes were united in 1934 as the parish and urban district of Braintree and Bocking, which was subsequently abolished in 1974 when the modern Braintree District was created. Several local organisations still include Braintree and Bocking in their names.[nb 1]
Braintree is bypassed by the modern-day A120 and A131 roads, while trains serve two stations in the town, at the end of the Braintree Branch Line from Witham.
The town is twinned with Pierrefitte-sur-Seine, France,[2] and gives its name to the towns of Braintree, Massachusetts and Braintree, Vermont, in the United States.[2]
