How to create pgsql sequence from controller?

Rails
1

(Frenchy, sorry =))

Hi everyone, i’m working on a web browser based game:
every player have got some ants and i want every ants of each player
to have a unique name:

Player 1:
ant 1
ant 2
ant 3
Player 2:
ant 1
ant 2
ant 3
ant 4
…

To do that i need to create player1_seq and player2_seq and increment
the player sequence whenever the player create an ant so i need to
create sequence whenever a player subscribe.

How to do that?

Thanks.

2

On 22 September 2011 22:42, Romain ‘Maz’ BILLOIR [email protected]
wrote:

Player 2:
ant 1
ant 2
ant 3
ant 4
…

To do that i need to create player1_seq and player2_seq and increment
the player sequence whenever the player create an ant so i need to
create sequence whenever a player subscribe.

Why not just use the id of the ant?
If you need them to start from 1 for each player then when you make an
new ant look up the highest number for that player’s ants and add one
to that.

Colin

3

The simple answer is it would be trivial to have ants have unique names
use
ant id.

THe simples i can see is to use player.ant.count (select + update )

do a count of ants for player before each batch creation

I thought of 4 other ways but this is the simplest.
On Sep 22, 2011 2:43 PM, “Romain 'Maz' BILLOIR” <
[email protected]> wrote:

Player 2:
How to do that?

Thanks.

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4

I agree Colin, i can’t use count…
and i can’t use ant’s id because every ants of every players got a
unique id, so, this may be possible:
Player 1:
ant 1, id = 1
ant 2, id = 2
ant 3, id = 5
Player 2:
ant 1, id = 3
ant 2, id = 4
ant 3, id = 6
ant 4, id = 7.

And the Colin’s solution isn’t good too, suppose:
Player 1:
ant 1, id = 1, name = 1
ant 2, id = 2, name = 2
ant 3, id = 3, name = 3

Player2 subscribe and create 3ants:
on the first ant’s creation i just put the name to 1 and the twice
follower just got the previously name+1, so:
ant 1, id = 4, name = 1
ant 2, id = 5, name = 2
ant 3, id = 6, name = 3

Player1 attacks Player2. The Player2’s ant which has got the id = 6,
name = 3 dies.
Player2 creates a new ant the “highest number for that player’s ants”
will be the ant which has got the id = 5, name = 2 so the next name
will be 3. Again.

Is there noway to create sequence from controller? I can also just set
a new column with the last used name. But i don’t want my ant’s table
to be “BIG”(don’t know how to say clearly what i don’t want).

5

On 23 September 2011 16:34, Curtis S. [email protected] wrote:

The simple answer is it would be trivial to have ants have unique names use
ant id.

THe simples i can see is to use player.ant.count (select + update )

do a count of ants for player before each batch creation

Using count will not work. Suppose there were three, numbers 1, 2 and
3. Suppose number 2 is deleted leaving 1 and 3. If a new one were
created it would get 3 again if count were used. It is necessary to
find the current highest and increment that so the new one will be 4.

Colin

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6

I can also just set
a new column with the last used name. But i don’t want my ant’s table
to be “BIG”(don’t know how to say clearly what i don’t want).

I meant a new column in the player’s city’s table, which can’t be
delete.

7

On 23 September 2011 19:50, Romain ‘Maz’ BILLOIR [email protected]
wrote:

ant 3, id = 6
ant 4, id = 7.

Your initial post did not say that there would be any problems with
the numbering above

ant 1, id = 4, name = 1
ant 2, id = 5, name = 2
ant 3, id = 6, name = 3

Player1 attacks Player2. The Player2’s ant which has got the id = 6,
name = 3 dies.
Player2 creates a new ant the “highest number for that player’s ants”
will be the ant which has got the id = 5, name = 2 so the next name
will be 3. Again.

Again, your initial post did not say that you must not use the same
number again. In that case you need a column in the players table
keeping the last used number for each player and use that to determine
the next ant number.

Is there noway to create sequence from controller?

I don’t understand what you mean. If the requirement is that each
player’s ants must start from 1 and increment for each ant, and a
number must not be re-used if an ant is destroyed then the only way of
achieving this is to keep a record for each player of the last used
number, and there is no sensible place to store it other than in the
players record.

Colin

gplus.to/clanlaw

8

He asked for unique it is true
On Sep 23, 2011 9:03 AM, “Colin L.” [email protected] wrote:

On 23 September 2011 16:34, Curtis S. [email protected] wrote:

The simple answer is it would be trivial to have ants have unique names
use

every player have got some ants and i want every ants of each player
ant 4

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Groups
“Ruby on Rails: Talk” group.
gplus.to/clanlaw

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9

If you want todo this with posygresl - you may be bettrr off using psql
and
a trigger and a sequence and adking in the plsql forum.

AND then please post what you doo!!
On Sep 22, 2011 2:43 PM, “Romain 'Maz' BILLOIR” <
[email protected]> wrote:

ant 3

How to do that?

Thanks.

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10

Ok, just find out the perfect solution, in my controller, i just did:

ActiveRecord::Base.connection.execute("CREATE SEQUENCE " +
current_user.username + “_id_seq”)

If someone see any problems with this solution, tell me.

11

Ok, i just find out the perfect solution. In my controller, i just do:

ActiveRecord::Base.connection.execute("CREATE SEQUENCE " +
current_user.username + “_id_seq”)

And my player_id_seq is created, just need now to do something like:

ActiveRecord::Base.connection.execute("SELECT nextval( " +
current_user.username + “_id_seq)”)

whenever an ant is created to get the next ant’s name =)

If someone see any problems i can encounter, please tell me.