SQL is a programming language designed to manage data stored in a relational database management system (RDBMS). SQL stands for the structured query language. It is pronounced as /ˈɛs kjuː ˈɛl/ or /ˈsiːkwəl/. SQL consists of a data definition language, data manipulation language, and a data control language. At a minimum, every SQL Server database has two operating system files: a data file and a log file. Data files contain data and objects such as tables, indexes, stored procedures, and views. Log files contain the information that is required to recover all transactions in the database.
Summary: this tutorial helps you answer the question: what is MySQL? And give you the reasons why MySQL is the world's most popular open-source database.
To understand MySQL, you first need to understand the database and SQL. If you already know database and SQL, you can jump to the What is MySQL section.
Introduction to database
You deal with data every day…
When you want to listen to your favorite songs, you open your playlist from your smartphone. In this case, the playlist is a database.
When you take a photo and upload it to your account on a social network like Facebook, your photo gallery is a database.
When you browse an e-commerce website to buy shoes, clothes, etc., you use the shopping cart database.
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Databases are everywhere. So what is a database? By definition, a database is merely a structured collection of data.
The data relating to each other by nature, e.g., a product belonged to a product category and associated with multiple tags. Therefore, we use the term relational database.
In the relational database, we model data like products, categories, tags, etc., using tables. A table contains columns and rows. It is like a spreadsheet.
A table may relate to another table using a relationship, e.g., one-to-one and one-to-many relationships.
Because we deal with a significant amount of data, we need a way to define the databases, tables, etc., and process data more efficiently. Besides, we want to turn the data into information.
And this is where SQL comes to play.
SQL – the language of the relational database
SQL stands for the structured query language.
SQL is the standardized language used to access the database.
ANSI/SQL defines the SQL standard. The current version of SQL is SQL:2016. Whenever we refer to the SQL standard, we mean the current SQL version.
SQL contains three parts:
- Data definition language includes statements that help you define the database and its objects, e.g., tables, views, triggers, stored procedures, etc.
- Data manipulation language contains statements that allow you to update and query data.
- Data control language allows you to grant the permissions to a user to access specific data in the database.
Now, you understand database and SQL, and it's time to answer the next question…
What is MySQL
MySQL? What?
My is the daughter's name of the MySQL's co-founder, Monty Widenius.
The name of MySQL is the combination of My and SQL, MySQL. Turbo 264 hd (mac app store) download free.
MySQL is a database management system that allows you to manage relational databases. It is open source software backed by Oracle. It means you can use MySQL without paying a dime. Also, if you want, you can change its source code to suit your needs.
Even though MySQL is open source software, you can buy a commercial license version from Oracle to get premium support services.
MySQL is pretty easy to master in comparison with other database software like Oracle Database, or Microsoft SQL Server.
MySQL can run on various platforms UNIX, Linux, Windows, etc. You can install it on a server or even in a desktop. Besides, MySQL is reliable, scalable, and fast.
The official way to pronounce MySQL is My Ess Que Ell, not My Sequel. However, you can pronounce it whatever you like, who cares?
If you develop websites or web applications, MySQL is a good choice. MySQL is an essential component of the LAMP stack, which includes Linux, Apache, MySQL, and PHP.
The spread of dynamic websites on the World Wide Web today is largely due to the possibility for their content to be handled through databases. Database management is a complicated process, which has been considerably rationalized by the SQL programming language. As its full name (Structured Query Language) implies, SQL is responsible for querying and editing information stored in a certain database management system.
Content:- SQL data control, definition and manipulation
SQL History
The origins of the SQL take us back to the 1970s, when in the IBM laboratories, new database software was created - System R. And to manage the data stored in System R, the SQL language was created. At first it was called SEQUEL, a name which is still used as an alternative pronunciation for SQL, but was later renamed to just SQL.
In 1979, a company called Relational Software, which later became Oracle, saw the commercial potential of SQL and released its own modified version, named Oracle V2.
Now into its third decade of existence, SQL offers great flexibility to users by supporting distributed databases, i.e. databases that can be run on several computer networks at a time. Certified by ANSI and ISO, SQL has become a database query language standard, lying in the basis of a variety of well established database applications on the Internet today. It serves both industry-level and academic needs and is used on both individual computers and corporate servers. With the progress in database technology SQL-based applications have become increasingly affordable for the regular user. This is due to the introduction of various open-source SQL database solutions such as MySQL, PostgreSQL, SQLite, Firebird, and many more.
SQL Standard
The SQL Standard has gone through a lot of changes during the years, which have added a great deal of new functionality to the standard, such as support for XML, triggers, regular expression matching, recursive queries, standardized sequences and much more. Due to SQL Standard's sheer volume, a lot of database solutions based on it, such as MySQL or PostgreSQL, do not implement the whole standard. In a lot of cases, the database behavior for file storage or indexes is not well defined and it's up to the vendors of the various SQL implementations to decide how the database will behave. This is the reason why, even though all SQL implementations have the same base, they are rarely compatible. Indigo renderer 4 0 38 download free.
SQL Language elements
The SQL language is based on several elements. For the convenience of SQL developers all necessary language commands in the corresponding database management systems are usually executed through a specific SQL command-line interface (CLI).
Clauses - the clauses are components of the statements and the queries
Expressions - the expressions can produce scalar values or tables, which consist of columns and rows of data
Predicates - they specify conditions, which are used to limit the effects of the statements and the queries, or to change the program flow
Queries - a query will retrieve data, based on a given criteria
Statements - with the statements one can control transactions, program flow, connections, sessions, or diagnostics. In database systems the SQL statements are used for sending queries from a client program to a server where the databases are stored. In response, the server processes the SQL statements and returns replies to the client program. This allows users to execute a wide range of amazingly fast data manipulation operations from simple data inputs to complicated queries.
SQL queries
The SQL queries are the most common and essential SQL operations. Via an SQL query, one can search the database for the information needed. SQL queries are executed with the 'SELECT' statement. An SQL query can be more specific, with the help of several clauses:
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- FROM - it indicates the table where the search will be made.
- WHERE - it's used to define the rows, in which the search will be carried. All rows, for which the WHERE clause is not true, will be excluded.
- ORDER BY - this is the only way to sort the results in SQL. Otherwise, they will be returned in a random order.
An SQL query example
SELECT * FROMWHERE active
ORDER BY LastName, FirstName
SQL data control, definition and manipulation
SQL is a language designed to store data, but the data stored in an SQL database is not static. It can be modified at any time with the use of several very simple commands. The SQL syntax is pretty much self explanatory, which makes it much easier to read and understand.
SQL data manipulation
Data manipulation is essential for SQL tables - it allows you to modify an already created table with new information, update the already existing values or delete them.
With the INSERT statement, you can add new rows to an already existing table. New rows can contain information from the start, or can be with a NULL value.
An example of an SQL INSERT
INSERT INTO phonebook(phone, firstname, lastname, address) VALUES('+1 123 456 7890', 'John', 'Doe', 'North America');With the UPDATE statement, you can easily modify the already existing information in an SQL table.
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An example of an SQL UPDATE
UPDATE phonebook SET address = 'North America', phone = '+1 123 456 7890' WHERE firstname = 'John' AND lastname = 'Doe';With the DELETE statement you can remove unneeded rows from a table.
An example of an SQL DELETE
DELETE FROM phonebook WHERE WHERE firstname = 'John' AND lastname = 'Doe';SQL data definition
Data definition allows the user to define new tables and elements.
CREATE - with the CREATE statement you can create a new table in an existing database.
An example of an SQL CREATE
CREATE TABLE phonebook(phone VARCHAR(32), firstname VARCHAR(32), lastname VARCHAR(32), address VARCHAR(64));DROP - with the DROP statement in SQL you can delete tables, which you no longer need
An example of an SQL DROP
DROP TABLE phonebook;TRUNCATE - with the TRUNCATE statement, you can delete all the content in the table, but keep the actual table intact and ready for further use
An example of an SQL TRUNCATE
TRUNCATE TABLE phonebook;The ALTER statement permits the user to modify an existing object in various ways -- for example, by adding a column to an existing table.
ALTER TABLE phonebook RENAME TO contacts
SQL data control
SQL allows the user to define the access each of the table users can have to the actual table.
GRANT - with the GRANT statement, you can authorize users to modify the selected table
An example of an SQL GRANT
GRANT ALL PRIVILEGES ON database_name TO database_user;REVOKE - with the REVOKE statement you can remove all privileges, previously granted to a user.
An example of an SQL REVOKE
REVOKE ALL PRIVILEGES ON database_name TO database_user ;
SQL with NTC Hosting
MySQL, one of the most famous SQL distributions used by the majority of the scripts on the Internet, is included in all web hosting plans offered by NTC Hosting. And for those who demand a more professional solution, each plan can be upgraded with PostgreSQL. Each web hosting package comes with special graphical interface tools for managing tables - phpMyAdmin and phpPgAdmin, for MySQL and PostgreSQL, respectively.