Tag: databases

How to cache MySQL / MariaDB query results

Contents 0. In MySQL, query caching has been completely removed in recent versions, while in MariaDB, on the contrary, it has become enabled by default. 1. How MySQL / MariaDB query caching works 2. When to use MySQL / MariaDB query caching 3. How to enable and configure MySQL / MariaDB query result caching 4. How to check MySQL /...

Should I close MySQL connections with $mysqli->close() in PHP scripts. Should I use $result->free()

Contents What are $mysqli->close() and $result->free() used for in PHP Is it necessary to close connections to MySQL / MariaDB and clear the result of the SQL query? When using $mysqli->close() and $result->free() will NOT give tangible results When to use $mysqli->close() and $result->free() Is it possible to close the MySQL database connection before completing the processing of query results...

How to list all current connections to MySQL and MariaDB databases

Contents List of running operations and processes on MySQL and MariaDB server How to view MySQL and MariaDB processes in real time What do the fields in the SHOW PROCESSLIST output mean How to display MySQL and MariaDB process data row by row instead of in a table Alternative syntax for SHOW FULL PROCESSLIST How to display only certain columns...

PHP Fatal error: Uncaught mysqli_sql_exception: Too many connections in (SOLVED)

Contents Error “Uncaught mysqli_sql_exception: Too many connections” Why does the “Too many connections” error occur How to temporarily increase the maximum number of connections to MySQL / MariaDB How to permanently increase the maximum number of connections to MySQL / MariaDB What is the maximum number of connections that can be established for MySQL and MariaDB 1. Error “Uncaught mysqli_sql_exception:...

How to transfer a database between DBMS servers without creating a database dump file (MySQL and MariaDB)

Contents Is it possible to transfer a database from one MySQL / MariaDB server to another without creating an intermediate file How to transfer a database from one server to another How to transfer a database from one MySQL/MariaDB instance to another when both MySQL/MariaDB instances are running on the same machine How to transfer a database from one MySQL/MariaDB...

How to run multiple MySQL/MariaDB server instances on one machine

Contents 1. Why you might want to run multiple MySQL or MariaDB servers on one computer 2. What you need to run multiple MySQL or MariaDB servers on one computer 3. Differences between MySQL and MariaDB when starting a second DBMS instance 4. Correcting the mariadb@.service file 5. How to configure a second MySQL or MariaDB instance 5.1 How to...

What do dots mean in MySQL and MariaDB SQL queries. How to refer from a table to a column in another table

Contents What do dots mean in MySQL and MariaDB SQL queries Identifier qualifiers in MySQL and MariaDB When to qualify a column name and when not to “ERROR 1046 (3D000): No database selected” / “#1046 - No database selected” even if qualified column names are used Conclusion Sources What do dots mean in MySQL and MariaDB SQL queries Consider the...

How to list columns in MySQL/MariaDB. How to check if a column exists in a table in PHP

Consider a situation where you need to find out whether a certain column exists in a table that is located in a database managed by a MySQL or MariaDB DBMS. In this post, we'll look at the SQL query syntax for getting a list of columns and searching for columns by name. We will also look at how to check...

How to increase the size of columns in phpMyAdmin

Table of contents 1. Why phpMyAdmin does not show the full contents of a cell (column) 2. How to view the full contents of a cell in phpMyAdmin 3. Why does changing column widths not show the entire data? 4.How to increase the number of characters in cells in phpMyAdmin Why phpMyAdmin does not show the full contents of a...

How to search in phpMyAdmin

Table of contents 1. How does searching through databases and tables work in phpMyAdmin 2. Instructions for using the search function in phpMyAdmin 3. Search the database as a whole. Search multiple tables simultaneously 4. Single table search Conclusion How does searching through databases and tables work in phpMyAdmin Searching MySQL/MariaDB is performed using SQL queries and therefore requires knowledge...
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