how to combine SQL queries in self.up

rubyonrails-talk
1

Hi

How can i combine multiple SQL statements into one place in self.up in a migration. For the following, method if i combine 3 SQL statements into one section I get the error.

######### following works fine def self.up       execute <<-EOF   CREATE TABLE pks (SNO TINYINT,BUSNO CHAR(20),EXPTIME TIME, PRIMARY KEY (SNO));       EOF       execute <<-EOF INSERT INTO pks (SNO,BUSNO,EXPTIME) VALUES('1','5L',080000);       EOF       execute <<-EOF INSERT INTO pks (SNO,BUSNO,EXPTIME) VALUES('2','5A',081500);       EOF

  end

########## it doesn't work

def self.up       execute <<-EOF   CREATE TABLE pks (SNO TINYINT,BUSNO CHAR(20),EXPTIME TIME, PRIMARY KEY (SNO)); INSERT INTO pks (SNO,BUSNO,EXPTIME) VALUES('1','5L',080000); INSERT INTO pks (SNO,BUSNO,EXPTIME) VALUES('2','5A',081500);       EOF

  end

2

ActiveRecord is available to you. Inside the self.up, you can do:

AnyArbitraryModel.connection.execute(all_of_your_sql)

Any model in your app will do, as you are bypassing your model's
business rules and going directly to the connection. The return is a
Mysql::Result, which you can look up here: Ruby/MySQL

Hope this helps.

3

You shouldn't need to, at least in the way you're asking about. Write your migrations in Ruby, not raw SQL.

because there is no other way i guess to have a non integer primary key in Rails framework --vipin

4

AnyArbitraryModel.connection.execute(all_of_your_sql)

but in my case, my whole of the data is static and i want to populate into the table at the time of migration itself. It is going to be like creation of table followed by insertion of 1000s of rows into them.

Will it work there too? If possible can you please explain the syntax of above command in the context of my problem.

--vipin

5

Vipin wrote: [...]

because there is no other way i guess to have a non integer primary key in Rails framework --vipin

Be careful! Rails *really* wants an integer primary key on most tables. Although it may be possible to do without it, I understand that problems may arise (Fred or other experts, can you confirm this?). My advice would be to let Rails put in the key that it wants. It won't hurt anything.

Best,

6

well...

I assume you're using a MySQL DB; If that is the case you actually need to specify specific options when connecting to the server to allow multiple queries in one statement. I've honestly never played with that before, but http://dev.mysql.com/doc/refman/5.0/en/c-api-multiple-queries.html should be a good start if you still want to go that route.

However, if your main concern is having a non-autoincrementing integer as the primary key (which is perfectly legitimate), its not hard. Write the migration is Ruby as normal, except also pass :id => false to the create_table method. Then run a query to alter table to add the primary key (you can also use this to add actual DB constraints and foreign keys and what not, although if you do this alot you're better off finding/writing a plugin to do this in a more Rubylike way). Finally in your model, use set_primary_key :name_of_primary_key_field.