Is there a way within Rails/AR to create a new mysql database at runtime?
What i recommend is to prepare standalone script readable only by specified user and execute it from rails with system command with db name as parammeter
The quick and dirty answer is:
Make sure the MySQL user your app is connecting as is allowed to create databases.
Create the database using a SQL statement:
ActiveRecord::Base.connection.execute('CREATE DATABASE IF NOT EXISTS new_database');
For simplicity's sake I'd suggest not even using ActiveRecord for this. AR is really designed to work with preconfigured databases, and even though you can create databases where you'll really run into problems is in trying to connect to and use those DBs on the fly.
You might be better off using Brian Lopez's mysql2 gem (in addition to AR for your app's main DB):
https://github.com/brianmario/mysql2
In addition to being pretty fast and modern, its API is a lot easier to work with than the raw mysql library (which is what AR uses under the hood, including connection.execute).
Related
I would like to build a data table that provides features like searching, filtering, free text search and so on (if anyone has more idea please share to create modern data table). My backend has to be in NodeJS and Front end could be simple html, css. If I need to create any middleware to make the data load faster, how will that be? Any suggestion regarding this will be very much apppreciated.
P.S: I have a mysql database.
Building a dynamic data table with a Node.js backend for a MySQL database can be a challenge, but there are a few libraries that can help you get the job done.
One library that can be used is the mysqljs/mysql library. This library provides a Node.js interface for MySQL databases. It can be used to create a connection to a MySQL database, run queries, and close the connection when finished.
Another library that can be used is the node-mysql2/promise library. This library provides a Node.js interface for MySQL databases with promise support. It can be used to create a connection to a MySQL database, run queries, and close the connection when finished.
Finally, the sequelize library can be used. This library provides an easy-to-use interface for interacting with MySQL databases. It can be used to create a connection to a MySQL database, define models, and run queries.
All of these libraries can be used to build a dynamic data table with a Node.js backend for a MySQL database.
I have been working on a project lately and using node as my back-end but instead of Mongodb I am using MySQL as my DBMS as I will need it in my project but I am having trouble organizing MySQL queries and can't find a good solution that helps me structure my code and files right. And another issue is that I don't know when to close my connection or if leaving it is a good practice or not.
NOTE: I already use express generator for generating my file architecture my only problem is where to place the MySQL related code and what are the best practices for a clean code.
You can create a model folder and add all your 'tables'.js there.
You can also create a DB.js file, so you can use Mysql from Nodejs and also manipulate it from the prompt:
Model Exemple
I.e of DB connection:
DB Connection
You can create tables on the way below. ID's, creating date and updated date are created automatically by Nodejs, so you don't need to worry about.
how to create a table
You also will need to download mySQL (npm install MySQL --save) and to interact with MySQL (selects, deletes,...)
Another way is create a repository.js and add SQL queries there, but is not really useful since you are using nodejs and it provides you these queries.
I am going to create a SaaS application in PHP. In that application the user can create and manage multiple tables to extend functionality. After user finish with the application he can download php code and database.
We will also provide sql import functionality so the user can create schema from (.sql) file.
I search on google but not found any proper solution. You can consider sqlfiddle functionality here.
I have 2 options in my mind but need better solution:
1) For creating multiple database and its tables, use table prefix as a solution
2) Convert mysql to sqlite. At the time of download create export as mysql (.sql) file.
It can have aprox. 10,000 users/databases. Please suggest a solution to provide each user a seperate database if any.
If shared server will not work I will purchase VPS. The main requirement is to provide each user their own database.
I am going to choose sqlite as a choice for db. After doing some benchmark sqlite seems good option for DDL and DML operation.
I will use mysql to sqlite .sql converter: https://github.com/sutara79/convert-mysql-to-sqlite
To improve the speed I follow following stackoverflow post:
Improve INSERT-per-second performance of SQLite?
So I'm moving from MS Access to MySQL:
In MS Access you can store certain INSERT, DELETE, and UPDATE queries as objects alongside your tables. Thus for anyone who don't understand computers that well, they can click on the objects and automatically run the queries to alter the master table for various business functions.
In MySQL, where and how do you store these queries, I seem to be only able to make tables. When I write a piece of code using the SQL editor, I can only save it to a remote location (such as my local desktop) and not onto the MySQL database, where it's accessible for my coworkers.
If you can't save it onto the server, how would I write a piece of code and execute it within the database that would be easily usable by others.
Thanks
The answer to this question is going to depend on your environment, your users, and your bandwidth to support any given solution. You are gaining a lot by making the switch from Access to MySQL, however you are losing some of the the WYSIWYG features. (e.g., Access forms that can bind directly to your data source.)
There are many approaches:
If your users are more advanced, simply having access to the database using MySQL Workbench may suffice. From there they would have access to run views, stored procedures, or to create their own custom queries.
Another option would be to script your objects using Python and provide a simple gui using TkInter. Python is generally thought of as an easy to use language; with built in suppport for MySQL and TkInter is its "default" interface.
Using the LAMP architecture is another largely popular paradigm using MySQL as the backend database.
There is also nothing stopping you from using Access to link to your MySQL db using MySQL as an external data source.
I hope this provides enough info to help you begin whittling down your options.
I am collecting data and store this data in a MySQL database using Java. Additionally, I use Maven for building the project, TestNG as a test framework, and Spring-Jdbc for accessing the database. I've implemented a DAO layer that encapsulates the access to the database. Besides adding data using the DAO classes I want to execute some queries which aggregate the data and store the results in some other tables (like materialized views).
Now, I would like to write some testcases which check whether the DAO classes are working as they should. Therefore, I thought of using an in-memory database which will be populated with some test data. Since I am also using MySQL-specific SQL queries for aggregating data, I went into some trouble:
Firstly, I've thought of simply using the embedded-database functionality provided by Spring-Jdbc to instantiate an embedded database. I've decided to use the H2 implementation. There I ran into trouble because of the aggregation queries, which are using MySQL-specific content (e.g. time-manipulation functions like DATE()). Another disadvantage of this approach is that I need to maintain two ddl files - the actual ddl file defining the tables in MySQL (here I define the encoding and add comments to tables and columns, both features are MySQL-specific); and the test ddl file that defines the same tables but without comments etc. since H2 does not support comments.
I've found a description for using MySQL as an embedded database which I can use within the test cases (http://literatitech.blogspot.de/2011/04/embedded-mysql-server-for-junit-testing.html). That sounded really promising to me. Unfortunately, it didn't worked: A MissingResourceExcpetion occurred "Resource '5-0-21/Linux-amd64/mysqld' not found". It seems that the driver is not able to find the database daemon on my local machine. But I don't know what I have to look for to find a solution for that issue.
Now, I am a little bit stuck and I am wondering if I should have created the architecture differently. Do someone has some tips how I should setup an appropriate system? I have two other options in mind:
Instead of using an embedded database, I'll go with a native MySQL instance and setup a database that is only used for the testcases. This options sounds slow. Actually, I might want to setup a CI server later on and I thought that using an embedded database would be more appropriate since the test run faster.
I erase all the MySQL-specific stuff out of the SQL queries and use H2 as an embedded database for testing. If this option is the right choice, I would need to find another way to test the SQL queries that aggregates the data into materialized views.
Or is there a 3rd option which I don't have in mind?
I would appreciate any hints.
Thanks,
XComp
I've created Maven plugin exactly for this purpose: jcabi-mysql-maven-plugin. It starts a local MySQL server on pre-integration-test phase and shuts it down on post-integration-test.
If it is not possible to get the in-memory MySQL database to work I suggest using the H2 database for the "simple" tests and a dedicated MySQL instance to test MySQL-specific queries.
Additionally, the tests for the real MySQL database can be configured as integration tests in a separate maven profile so that they are not part of the regular maven build. On the CI server you can create an additional job that runs the MySQL tests periodically, e.g. daily or every few hours. With such a setup you can keep and test your product-specific queries while your regular build will not slow down. You can also run a normal build even if the test database is not available.
There is a nice maven plugin for integration tests called maven-failsafe-plugin. It provides pre- and post- integration test steps that can be used to setup the test data before the tests and to cleanup the database after the tests.