English | 2020 | ASIN : B08K53Z23Y | 169 Pages | PDF, EPUB, AZW3, MOBI | 7.11 MB

SQL (Structured Query Language) is the programming language that we use to communicate with databases. Through this language, we can store data in a database and then change it, delete it, and retrieve it. It's a powerful tool that virtually every company in the world relies on in some way.

What is SQL?

SQL stands for "Structured Query Language" and can be pronounced as "SQL" or "sequel - (Structured English Query Language)". Defined, SQL is a query language used for accessing and modifying information in one or more data tables and rows of a database.

SQL Database Design

IBM first developed SQL in 1970s. Also it is an ANSI/ISO standard. It has become a Standard Universal Language used by most of the relational database management systems (RDBMS). Some of the RDBMS systems are: Oracle, Microsoft SQL server, Sybase etc.

Most of these have provided their own implementation extensions, thus enhancing their RDBMS system features and making it a powerful tool. These RDBMS systems, all use the popular SQL commands SELECT, UPDATE, DELETE, INSERT, WHERE in similar format.

SQL Database Table

SQL database is constructed of a number of tables. In a business, SQL tables would be used to divide and simplify the different areas of the operation: Table for Customers, one for Vendors, Employees and so on.

SQL Database Table Columns

Each SQL table is made up of a number of columns, referred to as fields and run along the top of the table. Sql columns or fields have their content (object/data/info) defined into character types; such as text, date, numeric, integer, length to name a few.

SQL Database Table Rows

Each SQL table row, referred to a record, is located in the left column of the table. Sql record row will contain a string of data containing data matching up to each column field across the top. So, in a "Customer table" each "customer record" would consist of one row with data for the customer ID number, customer name, address, phone ...email and so on.

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