{"componentChunkName":"component---src-templates-blog-post-js","path":"/blog/importing-data-into-docker-based-mysql","result":{"data":{"markdownRemark":{"html":"

Here is a \"cheatsheet\" for setting up a mysql server with Docker. If you're working with Wordpress, for example, the following should be fairly useful as you will need a working MySQL container for a typical local development setup for WP which usually involves importing an existing database. This article outlines a slight difference, depending on whether the mysql container is brand new or existing.

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Setting-up a fresh instance of MySQL

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The following section is applicable when we are starting from scratch - setting up a completely new database on our local machine where no prior data exists.

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When creating a MySQL container we can do some one-time init actions to import one or more .sql files, often useful when importing a mysqldump sql file and re-creating a production database on our local machine we would like to work with.

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The folder where this is run from contains the following:

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[ROOT folder]\n- ...\n- docker-entrypoint-initdb.d/\n  |\n  |-- 01-init.sql\n  |\n  |-- 02-additional-data.sql
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The docker-entrypoint-initdb.d sub-directory contains a mysql dump file.

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When exporting a database using PhpMyAdmin, the resulting file does not pre-select or pre-defined a database. In other words, we have to specify the target database where the exported SQL is supposed to go into.

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Here is a one liner that will import all SQL files inside the local sub-directory docker-entrypoint-initdb.d:

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docker run --name mysql-cont \n       -e MYSQL_ROOT_PASSWORD=password \\\n       -e MYSQL_DATABASE=wordpress \\\n       -p 3306:3306 -d \\\n       --mount type=bind,source=$(pwd)/docker-entrypoint-initdb.d,target=/docker-entrypoint-initdb.d \\\n       mysql:5.7
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What happens in the above line is that:

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IMPORTANT: this is done on a fresh new non-existent container that does not have any data (no volume is monted to /var/lib/mysql). If there were data present (by using a volume), the .sql files would be ignored!

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Importing data into existing Docker MySQL Container

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If a MySQL container we're working with already exists and has a mounted /var/lib/mysql directory then the init process described above will not work. The init script will realize that our MySQL container has some data in the data files folder (/var/lib/mysql) and will use whatever it finds there, ignoring all the .sql files we may have passed into Docker's /docker-entrypoint-initdb.d directory in the container.

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To import data into such an environment we would then have two options:

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  1. Use your favourite MySQL GUI admin tool to import data
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  2. Connect to mysql via Docker and run database import commands.
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We'll focus on #2 here.

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docker exec -i mysql-cont sh -c 'exec mysql -uroot -p\"$MYSQL_ROOT_PASSWORD\"' target_db_name < /some/path/on/your/host/target_db.sql
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What the above does is:

\n","excerpt":"Here is a \"cheatsheet\" for setting up a mysql server with Docker. If you're working with Wordpress, for example, the following should be fairly useful as you…","frontmatter":{"date":"28 October, 2021","path":"/blog/importing-data-into-docker-based-mysql","title":"Importing data into Docker-based mysql container"},"fields":{"readingTime":{"text":"3 min read"}}}},"pageContext":{}}}