How do you manually execute SQL commands in Ruby On Rails using NuoDB

Question

I'm trying to manually execute SQL commands so I can access procedures in NuoDB.

I'm using Ruby on Rails and I'm using the following command:

ActiveRecord::Base.connection.execute("SQL query")

The "SQL query" could be any SQL command.

Like for example I have a table called "Feedback" and when I execute the command:

ActiveRecord::Base.connection.execute("SELECT `feedbacks`.* FROM `feedbacks`")

This would only return a "true" response instead of sending me all the data requested.

This is the output on the Rails Console is:

SQL (0.4ms)  SELECT `feedbacks`.* FROM `feedbacks`
 => true

I would like to use this to call stored procedures in NuoDB but upon calling the procedures, this would also return a "true" response.

Is there anyway I can execute SQL commands and get the data requested instead of getting a "true" response?

Answer 1

The working command I'm using to execute custom SQL statements is:

results = ActiveRecord::Base.connection.execute("foo")

with "foo" being the sql statement( i.e. "SELECT * FROM table").

This command will return a set of values as a hash and put them into the results variable.

So on my rails application_controller.rb I added this:

def execute_statement(sql)
  results = ActiveRecord::Base.connection.execute(sql)

  if results.present?
    return results
  else
    return nil
  end
end

Using execute_statement will return the records found and if there is none, it will return nil.

This way I can just call it anywhere on the rails application like for example:

records = execute_statement("select * from table")

"execute_statement" can also call NuoDB procedures, functions, and also Database Views.

Answer 2

For me, I couldn't get this to return a hash.

results = ActiveRecord::Base.connection.execute(sql)

But using the exec_query method worked.

results = ActiveRecord::Base.connection.exec_query(sql)

Answer 3

Reposting the answer from our forum to help others with a similar issue:

@connection = ActiveRecord::Base.connection
result = @connection.exec_query('select tablename from system.tables')
result.each do |row|
puts row
end

Answer 4

res = ActiveRecord::Base.connection_pool.with_connection { |con| con.exec_query( "SELECT 1;" ) }

The above code is an example for

1. executing arbitrary SQL on your database-connection
2. returning the connection back to the connection pool afterwards

Answer 5

Once you get the MySql::Result object

results = ActiveRecord::Base.connection.execute(query)

You can convert it to array of rows

results.to_a

will make array of this format

[[row1][row2]...]