How do I run a ruby function inside an ActiveRecord query?
0
City.all.sample{rand(1..3)} I want the random function to generate the sample count. This always returns one record.
ruby activerecord ruby-on-rails-5
asked Nov 19 '18 at 9:46
tambakootambakoo
5510
|
show 1 more comment
0
City.all.sample{rand(1..3)} I want the random function to generate the sample count. This always returns one record.
ruby activerecord ruby-on-rails-5
asked Nov 19 '18 at 9:46
tambakootambakoo
5510
@iGian couple of hundred times. Less than a thousand.
– tambakoo
Nov 19 '18 at 10:24
1
[1, 2, 3, 4, 5, 6, 7].sample(rand(1..3))
– iGian
Nov 19 '18 at 10:30
@iGian that was super simple! Thanks.
– tambakoo
Nov 19 '18 at 10:34
sampleis not an active record query, though.
– Sergio Tulentsev
Nov 19 '18 at 10:38
1
@tambakoo: that it is, but you are not passing your logic to it. It runs unaltered. And thensampleacts on the results. And in general, you can't "pass a ruby function to be used in a query". That's the whole point of the databases: to filter/sort/return data with maximum efficiency.
– Sergio Tulentsev
Nov 19 '18 at 11:15
|
show 1 more comment
0
0
0
City.all.sample{rand(1..3)} I want the random function to generate the sample count. This always returns one record.
ruby activerecord ruby-on-rails-5
asked Nov 19 '18 at 9:46
tambakootambakoo
5510
City.all.sample{rand(1..3)} I want the random function to generate the sample count. This always returns one record.
ruby activerecord ruby-on-rails-5
ruby activerecord ruby-on-rails-5
asked Nov 19 '18 at 9:46
tambakootambakoo
5510
asked Nov 19 '18 at 9:46
tambakootambakoo
5510
asked Nov 19 '18 at 9:46
tambakootambakoo
5510
asked Nov 19 '18 at 9:46
tambakootambakoo
5510
asked Nov 19 '18 at 9:46
tambakootambakoo
5510
5510
@iGian couple of hundred times. Less than a thousand.
– tambakoo
Nov 19 '18 at 10:24
1
[1, 2, 3, 4, 5, 6, 7].sample(rand(1..3))
– iGian
Nov 19 '18 at 10:30
@iGian that was super simple! Thanks.
– tambakoo
Nov 19 '18 at 10:34
sampleis not an active record query, though.
– Sergio Tulentsev
Nov 19 '18 at 10:38
1
@tambakoo: that it is, but you are not passing your logic to it. It runs unaltered. And thensampleacts on the results. And in general, you can't "pass a ruby function to be used in a query". That's the whole point of the databases: to filter/sort/return data with maximum efficiency.
– Sergio Tulentsev
Nov 19 '18 at 11:15
|
show 1 more comment
@iGian couple of hundred times. Less than a thousand.
– tambakoo
Nov 19 '18 at 10:24
1
[1, 2, 3, 4, 5, 6, 7].sample(rand(1..3))
– iGian
Nov 19 '18 at 10:30
@iGian that was super simple! Thanks.
– tambakoo
Nov 19 '18 at 10:34
sampleis not an active record query, though.
– Sergio Tulentsev
Nov 19 '18 at 10:38
1
@tambakoo: that it is, but you are not passing your logic to it. It runs unaltered. And thensampleacts on the results. And in general, you can't "pass a ruby function to be used in a query". That's the whole point of the databases: to filter/sort/return data with maximum efficiency.
– Sergio Tulentsev
Nov 19 '18 at 11:15
@iGian couple of hundred times. Less than a thousand.
– tambakoo
Nov 19 '18 at 10:24
@iGian couple of hundred times. Less than a thousand.
– tambakoo
Nov 19 '18 at 10:24
1
1
[1, 2, 3, 4, 5, 6, 7].sample(rand(1..3))– iGian
Nov 19 '18 at 10:30
[1, 2, 3, 4, 5, 6, 7].sample(rand(1..3))– iGian
Nov 19 '18 at 10:30
@iGian that was super simple! Thanks.
– tambakoo
Nov 19 '18 at 10:34
@iGian that was super simple! Thanks.
– tambakoo
Nov 19 '18 at 10:34
sample is not an active record query, though.– Sergio Tulentsev
Nov 19 '18 at 10:38
sample is not an active record query, though.– Sergio Tulentsev
Nov 19 '18 at 10:38
1
1
@tambakoo: that it is, but you are not passing your logic to it. It runs unaltered. And then
sample acts on the results. And in general, you can't "pass a ruby function to be used in a query". That's the whole point of the databases: to filter/sort/return data with maximum efficiency.– Sergio Tulentsev
Nov 19 '18 at 11:15
@tambakoo: that it is, but you are not passing your logic to it. It runs unaltered. And then
sample acts on the results. And in general, you can't "pass a ruby function to be used in a query". That's the whole point of the databases: to filter/sort/return data with maximum efficiency.– Sergio Tulentsev
Nov 19 '18 at 11:15
|
show 1 more comment
1 Answer
1
active
oldest
votes
0
I'd suggest this way, to avoid retrieving all records:
n.times.map.with_object() { |_, a| a << City.find(City.ids.sample) }
It returns an array of records.
Of course, n can be a random integer.
answered Nov 19 '18 at 10:36
iGianiGian
3,6052622
Why notCity.order('RAND()').limit(rand(1..3))? (RAND(),RANDOM()) depending the DB.
– Sebastian Palma
Nov 19 '18 at 10:38
@SebastianPalma: terrible performance for larger tables.
– Sergio Tulentsev
Nov 19 '18 at 10:38
add a comment |
Your Answer
StackExchange.ifUsing("editor", function () {
StackExchange.using("externalEditor", function () {
StackExchange.using("snippets", function () {
StackExchange.snippets.init();
});
});
}, "code-snippets");
StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "1"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);
StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});
function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: true,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: 10,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});
}
});
draft saved
draft discarded
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f53371941%2fhow-do-i-run-a-ruby-function-inside-an-activerecord-query%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
0
I'd suggest this way, to avoid retrieving all records:
n.times.map.with_object() { |_, a| a << City.find(City.ids.sample) }
It returns an array of records.
Of course, n can be a random integer.
answered Nov 19 '18 at 10:36
iGianiGian
3,6052622
Why notCity.order('RAND()').limit(rand(1..3))? (RAND(),RANDOM()) depending the DB.
– Sebastian Palma
Nov 19 '18 at 10:38
@SebastianPalma: terrible performance for larger tables.
– Sergio Tulentsev
Nov 19 '18 at 10:38
add a comment |
0
I'd suggest this way, to avoid retrieving all records:
n.times.map.with_object() { |_, a| a << City.find(City.ids.sample) }
It returns an array of records.
Of course, n can be a random integer.
answered Nov 19 '18 at 10:36
iGianiGian
3,6052622
Why notCity.order('RAND()').limit(rand(1..3))? (RAND(),RANDOM()) depending the DB.
– Sebastian Palma
Nov 19 '18 at 10:38
@SebastianPalma: terrible performance for larger tables.
– Sergio Tulentsev
Nov 19 '18 at 10:38
add a comment |
0
0
0
I'd suggest this way, to avoid retrieving all records:
n.times.map.with_object() { |_, a| a << City.find(City.ids.sample) }
It returns an array of records.
Of course, n can be a random integer.
answered Nov 19 '18 at 10:36
iGianiGian
3,6052622
I'd suggest this way, to avoid retrieving all records:
n.times.map.with_object() { |_, a| a << City.find(City.ids.sample) }
It returns an array of records.
Of course, n can be a random integer.
answered Nov 19 '18 at 10:36
iGianiGian
3,6052622
answered Nov 19 '18 at 10:36
iGianiGian
3,6052622
answered Nov 19 '18 at 10:36
iGianiGian
3,6052622
answered Nov 19 '18 at 10:36
iGianiGian
3,6052622
3,6052622
Why notCity.order('RAND()').limit(rand(1..3))? (RAND(),RANDOM()) depending the DB.
– Sebastian Palma
Nov 19 '18 at 10:38
@SebastianPalma: terrible performance for larger tables.
– Sergio Tulentsev
Nov 19 '18 at 10:38
add a comment |
Why notCity.order('RAND()').limit(rand(1..3))? (RAND(),RANDOM()) depending the DB.
– Sebastian Palma
Nov 19 '18 at 10:38
@SebastianPalma: terrible performance for larger tables.
– Sergio Tulentsev
Nov 19 '18 at 10:38
Why not
City.order('RAND()').limit(rand(1..3))? (RAND(), RANDOM()) depending the DB.– Sebastian Palma
Nov 19 '18 at 10:38
Why not
City.order('RAND()').limit(rand(1..3))? (RAND(), RANDOM()) depending the DB.– Sebastian Palma
Nov 19 '18 at 10:38
@SebastianPalma: terrible performance for larger tables.
– Sergio Tulentsev
Nov 19 '18 at 10:38
@SebastianPalma: terrible performance for larger tables.
– Sergio Tulentsev
Nov 19 '18 at 10:38
add a comment |
draft saved
draft discarded
Thanks for contributing an answer to Stack Overflow!
- Please be sure to answer the question. Provide details and share your research!
But avoid …
- Asking for help, clarification, or responding to other answers.
- Making statements based on opinion; back them up with references or personal experience.
To learn more, see our tips on writing great answers.
draft saved
draft discarded
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f53371941%2fhow-do-i-run-a-ruby-function-inside-an-activerecord-query%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
@iGian couple of hundred times. Less than a thousand.
– tambakoo
Nov 19 '18 at 10:24
1
[1, 2, 3, 4, 5, 6, 7].sample(rand(1..3))– iGian
Nov 19 '18 at 10:30
@iGian that was super simple! Thanks.
– tambakoo
Nov 19 '18 at 10:34
sampleis not an active record query, though.– Sergio Tulentsev
Nov 19 '18 at 10:38
1
@tambakoo: that it is, but you are not passing your logic to it. It runs unaltered. And then
sampleacts on the results. And in general, you can't "pass a ruby function to be used in a query". That's the whole point of the databases: to filter/sort/return data with maximum efficiency.– Sergio Tulentsev
Nov 19 '18 at 11:15