I'm developing a system that have a Users table and a Books table.
I need to implement a Users search, and a results page showing all Users and all Books belonging to each user.
Currently, I'm using GROUP_CONCAT to get the Books of each User.
Alternatively, using LEFT JOIN brings duplicate results; Then I have to manipulate the data in PHP(is this 'better'?) Off course, I can't use GROUP BY as I need all Books.
I dont have any problems with GROUP_CONCAT, but now I need to filter by Book's and putting 'WHERE books.name like "% name%"' will filter the GROUP_CONCAT result, then showing just the searched book in the filter(while I need all users books)
Wich is the best method to do a search with One-to-Many results in PHP / MySQL ?
Related
This question is about selecting data from multiple tables, joins, Doctrine2, ResultSetMapping, DQL and such stuff.
I have 4 tables:
user
contact
contact_phone
call
With relations as shown on the image: http://i.stack.imgur.com/762Jw.png
Every user can have many contacts, each contact can have many phones and each user can have many calls to/from his contacts. Just like in the real world... I've limited the number of fields in each table just for clarity.
So my problem is that I don't know how exactly to map call numbers to contact names when showing a list of calls for a specific user.
If I want to list all calls of user 1 I do:
$callRepository = $this->getDoctrine()->getRepository('MyBundle:Call');
$calls = $callRepository->findAll(array('user' => 1));
But this will give me just the list of all calls for this user and will not associate number (call.number) with names (contact.name).
I can achieve what I want with plain SQL with this query:
SELECT
c.number,
contact.name
FROM
`call` c
JOIN contact_phone cp ON
cp.number = c.number
JOIN contact ON
contact.id = cp.contact_id
WHERE
c.user_id = contact.user_id
AND c.user_id = 1
Please note that I don't want to select all calls (with SQL) and then map numbers to names with another query from the PHP layer because this way I won't be able to search the calls by name for example.
I was thinking that ResultSetMapping could help me in this case but I have no luck putting the SQL query and the ResultSetMapping together.
Please help,
Thanks!
As per my knowledge, you can acheive by using the below methods. Please go to bottom of the page. you can find Joins... try once..
http://docs.doctrine-project.org/projects/doctrine1/en/latest/en/manual/dql-doctrine-query-language.html
I'm super new to CakePHP. I've searched everywhere for this but I can't seem to be able to get it right, or find any sort of orientation. I still don't get how the whole HABTM thing works and I'm expecting to learn more from this.
I'm trying to do a Twitter-like system, with users and followers, and posts (tweets) and shares (retweets). I've set up the users and posts models, and join tables for followers (between users and users) and shares (between users and posts). How should I set up my model associations? I've been trying several ways but I'm not certain on whether I'm doing it right or not.
And the other question is, what would be the proper find query to get all posts by the people I follow, plus the posts they've shared, without getting all the unnecessary data like user info and such, just the posts in one array? Is it possible with find in one query, or should I do several and then merge the arrays? Plus, it would be extremely useful to understand how to properly filter and limit this rather complex query (obtaining a "posts timeline" between certain date ranges, limit the posts to a certain amount, or both).
I know my question is a little bit silly, but I swear I've done a lot of research and I can't seem to be able to get it right. So any help, especially with the query part, would be greatly appreciated.
Thanks!
So these would be some weird relationships. I'm feeling you should have the following tables:
Users (with alias Followers) hasMany tweets
Posts belongsTo Users
UsersFollowers (A HABTM table)
To make this work on just three tables, Posts would need to be a threaded table. In essence, if a person retweets (shares) a post a new record is created with the id of the original post in the new posts parent_id column. Then when the record was called the model could pull up the additional data and include it in the feed.
The alias aspect of Users allows for the follower part to be done in just one table. To find followers of a person, search with one key of the table (follower_id) and to find the people a person follows just search with the other key (users_id).
As for the second part of your question, finds should be pretty easy in this setup, but you might want to read up on Containable and threaded queries. You could include timestamp columns in the tables so you could later do a search by date feature (or a post timeline).
I'm building a private social network with Yii that will have "comments" all over the site - in Profiles, Events pages, Group Threads, etc. When a user makes a post, they will be able to select the visibility of that content as:
Anyone
Registered Users Only
Friends Only
Custom (specific list of friends)
I'm trying to figure out how to model this for speed. I've considered using MySQL for writing the setting into a binary "is_secure" field in the Comments table - if it is true, then go to a table with three columns: comment_id, user_id, and group_id. Groups (group_id) would be for groups of users - Registered Users, Friends. Custom would make one row for each user that is selected (user_id).
This table will get huge (perhaps several dozen rows for each comment), so I'm wondering if using NoSQL is worth considering here for retrieval only, or if there's a better way to model this.
Thanks so much!
Similar question to database "flags". Search for related SO questions.
Instead of an IF true/false with the is_secure field, just add 1-bit fields for read_all (anyone), registered, friends, custom. Add another table which holds the custom list would have comment_id (from the previous table) and friend_id (multiple rows). That way, in a single query with a LEFT JOIN on custom_friends_list_for_comments you can determine whether or not to show the page to a user. Optionally, custom could be a comma separated list (char field) but size limits might be an issue. Assuming 3-letter friend ids with a comma, each 255 char field can have 64 friends.
I'm really hoping someone can help me with this. I have a number of product attribute types that users can select from to refine the products that are returned to them on screen. What I'm trying to do is, for each product attribute type, I want to list all attributes that relate to either the selected category or search term, then once they've made their selections, I still want to display each of the attributes that relate to the category or search term, but only display a clickable link if the product count for that particular attribute is greater than 1 and for those that have a product count of zero, I want to list them, but make them unclickable. An example of what I'm trying to achieve can be found on the ASOS website, in the left hand menu
http://www.asos.com/Women/Dresses/Cat/pgecategory.aspx?cid=8799#state=Rf961%3D3340%2C3341%40Rf-200%3D20&parentID=Rf-300&pge=0&pgeSize=20&sort=-1
Initially I tried using just joins to achieve this, but I wasn't able to do it, successfully. So I decided to create a temporary table for each attribute type which held a list of all the attributes that related to the main query and then created a refined query, with a left join. Here's my code:
CREATE TEMPORARY TABLE temp_table
SELECT su_types.id, type AS item FROM su_types
INNER JOIN su_typerefs ON su_types.id=su_typerefs.id
INNER JOIN su_pref ON su_typerefs.mykey = su_pref.mykey
WHERE wp_category_id =40 GROUP BY su_typerefs.id
$sudb->query($query);
if ($sudb->affected_rows > 0) {
SELECT temp_table.id,item,COUNT(su_typerefs.mykey) AS product_count FROM temp_table
LEFT JOIN su_typerefs ON temp_table.id=su_typerefs.id
LEFT JOIN su_pref ON su_typerefs.mykey = su_pref.mykey
LEFT JOIN su_stylerefs ON su_pref.mykey = su_stylerefs.mykey
LEFT JOIN su_productrefs ON su_pref.mykey = su_productrefs.mykey
WHERE wp_category_id =40 AND su_stylerefs.id in (91) AND su_productrefs.id in (54) AND su_typerefs.id in (159) GROUP BY su_typerefs.id
if ($itemresults = $sudb->query($query)) {
while($itemresult = $itemresults->fetch_array(MYSQLI_ASSOC)) {
$id=$itemresult['id'];
$item=$itemresult['item'];
$product_count=$itemresult['product_count'];
build_link($list_type, $item, $product_count, $id);
}
}
In the above example the first query selects all the product types that relate to a particular category, say dresses. And the second query is based on the refinements the user has made on the category, in this example this is product, product type and style. A user can also refine their search by colour, fit, fabric and design.
There are a couple of issues with this:
1) The number of results returned in the second query do not match the results of the first. Using the above as an example, I wish to list all products that relate to the chosen category, then using the second query return the product count for each of these products as I described above. So if the temporary table returns, trousers, jeans and skirts. I expected these three items to be displayed on screen based on the conditions applied in the second query, however my results may only show trousers and jeans, if there is not a match for skirts in the second query. I thought that using a left join would mean that all the results of the temporary table would be displayed.
2)Also I wonder if I'm doing this the most efficient way. I have a total of 8 attribute groups, and therefore need to do the above 8 times. If the user choses to refine the results using all 8 attribute groups then in addition to the temp table join, there will be a total of 9 joins for each type. It's taking a while to execute, is there a better way to do this? There are approximately 1/2 million products in the table, and this will probably be 5 times this, once my site goes live.
I really hope all that I have written makes sense and I'd really appreciate the stackoverflow community's help with this, if anyone can help. I apologise for the essay ;). Thanks in advance
To answer your first question; yes, a LEFT JOIN will indeed keep all data from the initial table. That, however, isn't the problem.
The reason why you lose empty categories, is most likely (I say this because I don't fully know your db structure) because of the where condition filtering out all results based on the data in the joined tables.
If for a category all items get filtered out (possibly including the NULL joined values), you will not get this category back from that query anymore. Also the GROUP BY is done on a joined column, that might also effectively wipe out your other categories.
As for the second question, you already state it's taking long; so it's probably not the way to go if you want things to work fast ;) (okay, obvious answer, low hanging fruit, etc). What you might want to do, is get a collection of keys from the filterable categories first, and use that data to select items.
This prevents that you have to join up your entire products table in a temp table (at least, that's what I think you're doing), which of course will take long with the given number of entries. Selecting a list of matching IDs from the given attributes also gives you the advance of using your indexes (more), which a temp-table probably won't have. If this is possible and feasible mainly depends on your schema's structure; but I hope it might lead you to the direction you want to go :)
So I have a User table and a History table with User hasMany Histories, and I'm trying to implement pagination on the user table.
My problem is that I have search, and some of the things one can search by are things in the History table. Is there a way to filter pagination results based on data in a table associated by hasMany? Containable, which initially seemed like a solution, allows such filtering but only in the retrieval of associated data, not the records themselves (unless I'm missing something?)
Has anyone had to solve this before?
Since it's a hasMany relationship, that means Cake will need to make 2 separate queries: 1 on the users table, and one on the histories table to retrieve all the associations. Since the History data isn't being retrieved until the 2nd query, then your 1st query cannot be filtered via WHERE conditions for fields found in the History model.
To resolve this, you can do one of two things:
Perform pagination on History using Containable (since History belongsTo User, meaning only 1 query will be performed).
Perform pagination on User the way you're already doing, except perform an ad-hoc join to History such that it's no longer a hasMany relationship.
e.g.:
$this->User->bindModel(array('hasOne' => array('History')));
$this->paginate['User']['contain'][] = 'History';
$this->paginate('User', array('History.some_field' => 'some_value'));