While some databases act as tables, some databases are more complex than that and act as tables that can point to other tables. These are referred to as relational databases. Databases are managed by database management systems (DBMSes), which generally use SQL to manipulate the data within.
- [Instructor] A database is a structured collection of data. Databases are used to store bits of information such as addresses, inventory, hotel names or just about anything. Depending on the database, a user may access it by a graphical interface, a command-line interface, or these days, it's very common to access them from a website. The majority of modern websites are actually created on the fly from data stored in databases. Anytime you buy products or services online from companies like Amazon or Expedia, they're querying a database for that information.
Your user and order information is then stored in the database as well. One of the most important characteristics of a database is the ability filter a query so only the information that the user is interested in is displayed. A database is the file the structured data is stored in. To access or manipulate the database, you'll need a database management system or DBMS. A DBMS is a piece of software that allows users to create, store, update, delete, and read data from the database. Examples of database management systems would be MariaDB which this course is on.
MySQL which this course also covers. As well as Oracle, IBM Db2, PostgreSQL, and Microsoft SQL Server. These DBMSs use a standardized language for manipulating databases, SQL or structured query language. There are differences in the SQL used, but all of the DBMSs that I mentioned use dialects of SQL. You will hear SQL pronounced SQL as well as SQL, the latter is the case with Microsoft's product, SQL Sever.
However, since SQL is an abbreviation, I will be pronouncing each letter individually as I would IBM or HP. In the case of products such as Microsoft SQL Server, I will pronounce it the way they do, since it's a trademarked product name. A database management system like MariaDB can be used to create and delete databases, administer structure, configure access control, back up databases, and restore databases, as well as manage performance, and handle reading and writing of the data to the database. By creating database users, we can separate the realm of power between database administrators and users.
A database admin can administer and maintain the database, and a user can add, update, or delete information in it. None of the users in the database need to be users in the operating system, as they often can keep separate access controls. Relational databases are comprised of one or more tables. Each table is comprised of rows and columns. Each row represents a single record made of columns of values. A column of unique values, serves as a primary key to keep records from being duplicated.
Multiple tables can be linked together with a foreign key. When reading the foreign key, it pulls in data from both tables. This allows a single field in a table, to point to a field in a different table. In some cases, it may point to multiple other fields.
- Installing MariaDB server
- MariaDB commands, configuration files, and logs
- Addressing SELinux concerns
- Using the MySQL shell
- Managing databases and tables with subcommands
- Creating a database with tables
- Querying a database
- Renaming tables and updating records
- Setting and recovering the root database password
- Securing your MariaDB server installation
- Performing and restoring logical database backups