Edgar F. Codd, a forerunner of the relational model for databases, presented a set of thirteen rules (numbered zero to twelve) to specify what is needed from a database management system in order for it to be regarded as a relational database management system (RDBMS). They're also known as "Codd's Twelve Commandments." Rule 0: The fundamental principle Any system that claims to be a relational database management system must be capable of managing databases only using its relational capabilities. Rule 1: The information rule A clear logical representation of every piece of information in a relational database is provided ... Read More

In some situations, such as backing up data and duplicating the production data for testing, copying data from an existing table to a new one is highly helpful. With the help of the MySQL copy or clone table feature, we may make an exact replica of an existing table, complete with its structure, indexes, constraints, default values, etc. In a circumstance like backing up data in case of table failure, copying data from an existing database onto a new table is quite helpful. You may use the CREATE TABLE and SELECT queries to replicate data from one table to another ... Read More

A deductive database in SQL or any other database system is a tool that can draw conclusions about new facts based on the rules and information already present in the database. In deductive databases, datalog is the language commonly used to express facts, rules, and queries. The formula, when expressed in clausal form, consists of a number of clauses, each of which is made up of a number of literals joined exclusively by logical connectives marked with the OR symbol. The following quantifiers are possible in a formula − Universal quantifier − It may be read as "For all x, ... Read More

As a developer or system administrator, it's crucial to ensure your MySQL database is running optimally to prevent downtime and maintain fast response times. Fortunately, Linux offers a range of powerful command-line tools that allow you to monitor MySQL's performance in real-time and diagnose any issues that may arise. In this article, we will explore four useful command-line tools that you can use to monitor MySQL performance in Linux. Top Command The top command is a popular Linux utility that enables you to monitor overall system performance, including MySQL processes. top command displays a real-time view of system's CPU usage, ... Read More

Introduction Docker Compose is a tool for defining and running multi-container Docker applications. It allows developers to define their application stack as a YAML file, making it easy to spin up complex environments with just a few commands. However, using private repositories with Docker Compose can be tricky. In this article, we'll explore how to use Docker Compose with private repositories, covering different authentication methods and their examples. What are Private Repositories? Docker images can be stored in private or public repositories. Public repositories are open to everyone, while private repositories require authentication to access them. Private repositories are often ... Read More

Introduction Docker is a popular platform for deploying and running applications in a containerized environment. It provides an efficient way to package, distribute and run applications with all their dependencies. One of main advantages of using Docker is that it enables use of multiple databases in an efficient way using docker-compose. Docker-compose is a tool for defining and running multi-container Docker applications. It allows you to define configuration of different containers in a single YAML file, which can be used to start, stop and manage containers. In this article, we will discuss how to use multiple databases with Docker-compose. Prerequisites ... Read More

The important statistics collected for a performed query, including time, temporary tables, indexes, joins, and more, are gathered in the Query Stats SQL editor results tab (see the following two figures). Requirements Enabled query, and collect performance schema statistics. The performance_schema has statement instrumentation enabled. SQL Editor: Query Stats Visual Explain Plan By utilizing the additional data included in the enhanced JSON format, the visual explain feature creates and presents a visual depiction of the MySQL EXPLAIN statement. All EXPLAIN formats, including the standard format, the raw extended JSON, and the visual query plan, are available in ... Read More

The controls listed below can be used to examine and export performance report data (see the following figure) − Export − Export all entries from the current performance report, including all queries and values, together with any associated data (including column headings). opens an export file dialogue. Copy Selected − Copies a single entry from the current performance report together with any related data (and column titles). the system's clipboard is saved. a case in point Query Copy − This function copies the SQL statement that produced the performance report. the system clipboard is saved. Refresh − The performance ... Read More

The MySQL system variable values are displayed using SHOW VARIABLES. There is no privilege required for this statement. Only the ability to connect to the server is necessary. Syntax SHOW [GLOBAL | SESSION] VARIABLES [LIKE 'pattern' | WHERE expr] A LIKE clause, if present, tells SHOW VARIABLES which variable names to match. To choose rows based on broader criteria, use a WHERE clause. An optional global or session variable scope modification is accepted by SHOW VARIABLES − The statement displays values for global system variables when GLOBAL is used as a modifier. For new connections ... Read More

The handling of missing or incorrect values in queries that change the data is governed by MySQL Strict Mode. This contains the CREATE TABLE, UPDATE, and INSERT statements. When attempting to process the query with MySQL Strict Mode enabled, which is the default setting, invalid or missing data may result in warnings or failures. When Strict Mode is turned off, the identical query would have its missing or incorrect data modified and would result in a straightforward warning. This could appear to be the desired outcome, but with Strict Mode turned off, certain activities might have unanticipated effects. For instance, ... Read More