Mysql – How to seed thesql database by running sql scripts in Ruby Rails platform

databaseMySQLrubyruby-on-rails

I have been basically java programmer and beginner for Ruby Rails. In java, to seed database ant task is run, the ant task execute SQL script. SQL script is basically set of insert statements.

I expect there must be some equivalent of ant task on Ruby Rails platform for running sql script?

Edited in response to answer by Nikita:

Although one can use Migration as one of way for seeding data. But I don't want to do rework of writing migration classes corresponding to sql scripts. so i need some solution through which i have to exec sql script file only. I want to manage by database only through sql code.

Best Answer

I personally don't like using migrations to seed large amounts of "static" data. You can easily execute sql statements from db/seeds.rb by:

# Empty the soon-to-be-seeded table
MyModel.delete_all

# Get the current DB connection
connection = ActiveRecord::Base.connection();

# Execute a sql statement
connection.execute("Insert INTO my_models (id, name) VALUES
    (1, 'Example 1'),
    (2, 'Example 2'),
    (3, 'Example 3');")

Basically, once you have the current connection, you can just call a sql statement useing connection.execute("SQL CODE HERE").

Related Solutions

Mysql – How to quickly rename a MySQL database (change schema name)

For InnoDB, the following seems to work: create the new empty database, then rename each table in turn into the new database:

RENAME TABLE old_db.table TO new_db.table;

You will need to adjust the permissions after that.

For scripting in a shell, you can use either of the following:

mysql -u username -ppassword old_db -sNe 'show tables' | while read table; \ 
    do mysql -u username -ppassword -sNe "rename table old_db.$table to new_db.$table"; done

for table in `mysql -u root -ppassword -s -N -e "use old_db;show tables from old_db;"`; do mysql -u root -ppassword -s -N -e "use old_db;rename table old_db.$table to new_db.$table;"; done;

Notes:

There is no space between the option -p and the password. If your database has no password, remove the -u username -ppassword part.
If some table has a trigger, it cannot be moved to another database using above method (will result Trigger in wrong schema error). If that is the case, use a traditional way to clone a database and then drop the old one:

mysqldump old_db | mysql new_db
If you have stored procedures, you can copy them afterwards:

mysqldump -R old_db | mysql new_db

Ruby-on-rails – How to “pretty” format JSON output in Ruby on Rails

Use the pretty_generate() function, built into later versions of JSON. For example:

require 'json'
my_object = { :array => [1, 2, 3, { :sample => "hash"} ], :foo => "bar" }
puts JSON.pretty_generate(my_object)

Which gets you:

{
  "array": [
    1,
    2,
    3,
    {
      "sample": "hash"
    }
  ],
  "foo": "bar"
}

Best Answer

Related Solutions

Mysql – How to quickly rename a MySQL database (change schema name)

Ruby-on-rails – How to “pretty” format JSON output in Ruby on Rails

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