As the manual says in Copying Databases you can pipe the dump directly into the mysql client: If you’re using MyISAM you could copy the files, but I wouldn’t recommend it. It’s a bit dodgy. Integrated from various good other answers Both mysqldump and mysql commands accept options for setting connection details (and much more), like: Also, if the new database is not … Read more
Assume a table structure of MyTable(KEY, datafield1, datafield2…). Often I want to either update an existing record, or insert a new record if it doesn’t exist. Essentially: What’s the best performing way to write this?
From the MySQL manual INSERT statements that use VALUES syntax can insert multiple rows. To do this, include multiple lists of column values, each enclosed within parentheses and separated by commas. Example:
You need to download and install SQL LocalDB. It is a special edition of SQL Server that does not allow remote connection and supports windows integrated authentication only. It is a simple one click MSI install so it is easy to deploy. To download and install SQL Server 2016 Express, go to SQL Server downloads. LocalDB is a … Read more
Something cool that is in version 5.0.37 of the community server is MySQL’s new profiler. This may give you what info you are looking for.
If you just need to know if a db exists so you won’t get an error when you try to create it, simply use (From here):
Since filter returns a QuerySet, you can use count to check how many results were returned. This is assuming you don’t actually need the results. After looking at the documentation though, it’s better to just call len on your filter if you are planning on using the results later, as you’ll only be making one sql query: A count() call … Read more
In phpMyAdmin, click the table, and then click the Import tab at the top of the page. Browse and open the csv file. Leave the charset as-is. Uncheck partial import unless you have a HUGE dataset (or slow server). The format should already have selected “CSV” after selecting your file, if not then select it … Read more
db:migrate runs (single) migrations that have not run yet. db:create creates the database db:drop deletes the database db:schema:load creates tables and columns within the existing database following schema.rb. This will delete existing data. db:setup does db:create, db:schema:load, db:seed db:reset does db:drop, db:setup db:migrate:reset does db:drop, db:create, db:migrate Typically, you would use db:migrate after having made changes to the schema via new migration … Read more
Triggers – a trigger is a piece of SQL to execute either before or after an update, insert, or delete in a database. An example of a trigger in plain English might be something like: before updating a customer record, save a copy of the current record. Which would look something like: The difference between … Read more