How to Execute Custom SQL Queries in Rails 3 Without Using a Model?

Rails 3 Custom SQL Queries Without Model

In Rails 3, executing custom SQL queries without using a model can be achieved by establishing a direct connection to the database. However, the code you provided encountered an issue with the execute method.

To address this, you can use the following approach:

1. Establish a connection to the database using ActiveRecord::Base.establish_connection.
2. Retrieve the connection object using ActiveRecord::Base.connection.
3. Execute the custom SQL query using connection.execute.

Here's a modified version of your code that incorporates these changes:

@connection = ActiveRecord::Base.establish_connection(
  :adapter => "mysql2",
  :host => "localhost",
  :database => "siteconfig_development",
  :username => "root",
  :password => "root123"
)

results = @connection.connection.execute("select * from users")
results.each do |row|
  puts row[0]
end

Alternatively, as suggested in the provided solution, you can also use the :as => :hash option while iterating over the results to access the columns by their names:

@connection = ActiveRecord::Base.establish_connection(
  :adapter => "mysql2",
  :host => "localhost",
  :database => "siteconfig_development",
  :username => "root",
  :password => "root123"
)

sql = "SELECT * from users"
@result = @connection.connection.execute(sql)
@result.each(:as => :hash) do |row|
  puts row["email"]
end

By using this approach, you can execute custom SQL queries directly without relying on a model.

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