Problem with displaying news from database!
Screenshoot:
Database(table) Articals: ID, Title, Content, User
Very simple, i only want display last 3 news from database with foreach in view
(my controller send me array of 3 records in $artical, and this is ok), but view cannot
display this..
please help me, my dead line is tomorrow.
In cakephp if you put into your tables the field created and modified (DATETIME), the mvc automatically insert the date of creation or when you modify it.
So when you retrieve your data you can do in this mode
$articals = $this->Artical->find('all', array(
'limit' => 3,
'order' => 'Artical.created DESC' )
));
or in your case if you an increment id you can do in this mode (but I suggest you to use created and insert it into your tables)
$articals = $this->Artical->find('all', array(
'limit' => 3,
'order' => 'Artical.ID DESC' )
));
If you have some problem to print data try to make a var_dump($articals);
After try to print out your content like this:
foreach ($articals as $artical) {
echo '<p>'.$artical['Artical']['Content'].'</p>';
}
Related
I have code like this:
$this->db->select('title')->from('entries')->where('id', 1);
$query = $this->db->get();
echo $query->row('title');
Which echoes the title from the entries table where the id is equal to 1.
Why doesn't it work without the 'title in row function?
echo $query->row();
As it returns the first row?
Why do I have to have 'title' in both places ($query->row and $this->db->select), in order for this to work? It doesn't make sense to me.
Can anybody explain how this works, supposedly provide with alternative ways to get the value from the database?
$this->db->select('title')->from('entries')->where('id', 1);
Generates
SELECT title FROM entries WHERE id = 1
$query retrieves the result in an array:
array( [0] => array( [title] => 'your title' ))
row('title') returns the title column from the first row of your result array.
The reason you need to tell it which column to get is because row and get can be used with many columns.
i use Active record for inserting values to DB.
All other type of queries i do with custom query as it's much easier but the active record insert is quite nice.
So i have this code :
$comment = array (
'point_id' => $object->id,
'title' => $object->title,
'comment' => $object->comment,
'author_name' => $object->author_name,
'is_temp' => 0,
'parent_id' => $object->parent_id
);
return $this->db->insert('comments', $comment);
Now i want to be able to set is_temp as a subquery result, which is :
(SELECT allow_user_comments from subjects where id='somevalue')
How would one achive that?
I was hoping to avoid using third party libraries.
Well, i doubt the fact that that's how you're supposed to do it, but ain't CI all about that?
This is how i got it to work (removing is_temp from the $comment array ofcourse):
$this->db->set($comment);
$this->db->set('is_temp',
'(SELECT allow_user_comments from subjects where id='.$subject_id.')',FALSE);
$this->db->insert('comments');
Feel free to use https://github.com/NTICompass/CodeIgniter-Subqueries. I have used it and it works! Hope it would be useful. :-)
I have 2 dates (create, update) that i want to merge in a new column, selecting the newest date... how can I do it?
Here is the array creation:
$this->Message= array(
'fields' => array('Message.id','Message.type','Message.createdate','Message.updatedate'),
'conditions' => $cond);
$messages = $this->Message->find('all', $conditionsMessage);
Now I need another field (lets call it NewDate) Message.NewDate that gets the newest date from Message.createdate and Message.updatedate, so i can call it after in a view using $messages[NewDate]
Help plz...
Thx!
UPDATE:
It's not hard to loop over the array with something like
foreach($messages as $k => $m){
if(strtotime($m['Message']['updatedate']) > strtotime($m['Message']['createdate'])){
$messages[$k]['Message']['NewDate'] = $m['Message']['updatedate'];
}else{
$messages[$k]['Message']['NewDate'] = $m['Message']['createdate'];
}
}
ORIGINAL ANSWER:
I would think that your Message.updatedate would always be the newest date, so you could just select that. But assuming that's not the case for some reason, you can create a virtual field in your model:
public $virtualFields = array(
'NewDate' => "IF(Message.updatedate > Message.createdate, Message.updatedate, Message.createdate)"
);
This uses the MySQL IF() function. If you're not using MySQL you'd have to figure out how to do something similar with your database.
http://dev.mysql.com/doc/refman/5.0/en/control-flow-functions.html#function_if
I came across an article about Join decomposition.
SCENARIO #1 (Not good):
Select * from tag
Join tag_post ON tag_post.tag_id=tag.id
Join post ON tag_post.post_id=post.id
Where tag.tag='mysql'
SCENARIO #2 (good):
Select * from tag where tag='mysql'
Select * from tag_post Where tag_id=1234
Select * from post where post.id in (123,456,9098,545)
It was suggested to stick to scenario #2 for many reasons specially caching.
The question is how to join inside our application. Could u give us an example with PHP
after retrieving them individually?
(I have read MyISAM Performance: Join Decomposition?
but it did not help)
You COULD use an SQL subselect (if I understand your question). Using PHP would be rather odd while SQL has all the capabilities.
SELECT *
FROM `post`
WHERE `id` IN (
SELECT `post_id`
FROM `tag_post`
WHERE `tag_id` = (
SELECT `tag_id`
FROM `tag`
WHERE `tag` = 'mysql'
)
)
I'm not sure how your database structure looks like, but this should get you started. It's pretty much SQL inception. A query within a query. You can select data using the result of a subselect.
Please, before copying this SQL and telling me it's not working, verify all table and column names.
Before anyone starts to cry about speed, caching and efficiency: I think this is rather efficient. Instead of selecting ALL data and loop through it using PHP you can just select smaller bits using native SQL as it was ment to be used.
Again, I highly discourage to use PHP to get specific data. SQL is all you need.
edit: here's your script
Assuming you have some multi-dimensional arrays containing all data:
// dummy results
// table tag
$tags = array(
// first record
array(
'id' => 0,
'tag' => 'mysql'
),
// second record
array(
'id' => 1,
'tag' => 'php'
)
// etc
);
// table tag_post
$tag_posts = array(
// first record
array(
'id' => 0,
'post_id' => 0, // post #1
'tag_id' => 0 // has tag mysql
),
// second record
array(
'id' => 1,
'post_id' => 1, // post #2
'tag_id' => 0 // has tag mysql
),
// second record
array(
'id' => 2,
'post_id' => 2, // post #3
'tag_id' => 1 // has tag mysql
)
// etc
);
// table post
$posts = array(
// first record
array(
'id' => 0,
'content' => 'content post #1'
),
// second record
array(
'id' => 1,
'content' => 'content post #2'
),
// third record
array(
'id' => 2,
'content' => 'content post #3'
)
// etc
);
// searching for tag
$tag = 'mysql';
$tagid = -1;
$postids = array();
$results = array();
// first get the id of this tag
foreach($tags as $key => $value) {
if($value['tag'] === $tag) {
// set the id of the tag
$tagid = $value['id'];
// theres only one possible id, so we break the loop
break;
}
}
// get post ids using the tag id
if($tagid > -1) { // verify if a tag id was found
foreach($tag_posts as $key => $value) {
if($value['tag_id'] === $tagid) {
// add post id to post ids
$postids[] = $value['post_id'];
}
}
}
// finally get post content
if(count($postids) > 0) { //verify if some posts were found
foreach($posts as $key => $value) {
// check if the id of the post can be found in the posts ids we have found
if(in_array($value['id'], $postids)) {
// add all data of the post to result
$results[] = $value;
}
}
}
If you look at the length of the script above, this is exactly why I'd stick to SQL.
Now, as I recall, you wanted to join using PHP, rather doing it in SQL. This is not a join but getting results using some arrays. I know, but a join would only be a waste of time and less efficient than just leaving all results as they are.
edit: 21-12-12 as result of comments below
I've done a little benchmark and the results are quite stunning:
DATABASE RECORDS:
tags: 10
posts: 1000
tag_posts: 1000 (every post has 1 random tag)
Selecting all posts with a specific tag resulted in 82 records.
SUBSELECT RESULTS:
run time: 0.772885084152
bytes downloaded from database: 3417
PHP RESULTS:
run time: 0.086599111557
bytes downloaded from database: 48644
Please note that the benchmark had both the application as the database on the
same host. If you use different hosts for the application and the database layer,
the PHP result could end up taking longer because naturally sending data between
two hosts will take much more time then when they're on the same host.
Even though the subselect returns much less data, the duration of the requests is nearly 10 times longer...
I've NEVER expected these results, so I'm convinced and I will certainly use this information when I know that performance is important however I will still use SQL for smaller operations hehe...
I want the user to be able to choose a restaurant from a dropdown list. I'm achieving this by the simple:
echo $this->Form->input(
'Restaurant', array('multiple'=>false, array('empty' => true)));
The issue I have is: some restaurants have duplicate names, and I need a way for the user to know which is which. I'd like to have the ID and/or address within the select options like:
<li value='62'>McDonalds (1234 Happy St) - #62</li>
<li value='63'>McDonalds (9876 French Fry Ln) - #63</li>
...etc
Is there a way to do this? I'm obviously capable of doing it w/ normal HTML, but... would be nice to stay in CakePHP.
Thanks ahead of time for any thoughts/suggestions/direction!
When you load your restaurants you're actually getting an array like this
array (
ID => NAME,
ID => NAME
)
Basically, it's an associated array with the ID as the key and the display field as the value. So as long as you modify that array via the find operation or via normal PHP array iteration, you can achieve your goal.
EDIT
So your answer is CakePHP VirtualFields
In your model you define it as
var $virtualFields = array(
'rest_unique_name' => 'CONCAT(Restaurant.first_name, " ", Restaurant.address)'
);
In your controller you do this
$opts = array(
'fields' => array('id', 'rest_unique_name')
);
$restaurants = $this->Restaurant->find('list', $opts);