I am building a fantasy football application where i have a table that stores all players . I have design the table as shown below . So far the system works when the formation is 4-4-2 where one goalkeeper is out , one defender is out and one forward is out and making changes to the squad is as easy as switching the players inside with the one on the bench .
The problem comes because i want to have multiple formations like 3-5-2 , 5-4-1 and so forth , i don't know how to save this to the database so as when someone view the changed team , he can see for example two defenders out when formation is 3-5-2 . I already achieved the frontend using javascript , the issue is the backend . Any help will be appreciated as i run out of options .
A possible solution could be using the following tables
user
id | team_name | current_formation_id
1 | Masaki | 1
2 | Other | 3
formation
id | desc | defenders_count | midfielders_count | forwarders_count
1 | 442 | 4 | 4 | 2
1 | 433 | 4 | 3 | 3
1 | 352 | 3 | 5 | 2
player
id | name | role | whatever_else
1 | P1 | MID | ...
2 | P2 | DEF | ...
3 | P3 | FWD | ...
user_roster
user_id | player_id | is_on_field
1 | 1 | 1
1 | 2 | 0
1 | 3 | 1
This way you could have the flexibility of changing the formation without altering the tables structure, you could know with a simple query which players are on the bench and which are playing, and you could also easily check if the current players respect the current formation counts.
Related
I created a table (t_subject) like this
| id | description | enabled |
|----|-------------|---------|
| 1 | a | 1 |
| 2 | b | 1 |
| 3 | c | 1 |
And another table (t_place) like this
| id | description | enabled |
|----|-------------|---------|
| 1 | d | 1 |
| 2 | e | 1 |
| 3 | f | 1 |
Right now data from t_subject is used for each of t_place records, to show HTML dropdowns, with all the results from t_subject.
So I simply do
SELECT * FROM t_subject WHERE enabled = 1
Now just for one of t_place records, one record from t_subject should be hidden.
I don't want to simply delete it with javascript, since I want to be able to customize all of the dropdowns if anything changes.
So the first thing I though was to add a place_id column to t_subject.
But this means I have to duplicate all of t_subject records, I would have 3 of each, except one that would have 2.
Is there any way to avoid this??
I thought adding an id_exclusion column to t_subject so I could duplicate records only whenever a record is excluded from another id from t_place.
How bad would that be?? This way I would have no duplicates, so far.
Hope all of this makes sense.
While you only need to exclude one course, I would still recommend setting up a full 'place-course' association. You essentially have a many-to-many relationship, despite not explicitly linking your tables.
I would recommend an additional 'bridging' or 'associative entity' table to represent which courses are offered at which places. This new table would have two columns - one foreign key for the ID of t_subject, and one for the ID of t_place.
For example (t_place_course):
| place_id | course_id |
|----------|-----------|
| 1 | 1 |
| 1 | 2 |
| 1 | 3 |
| 2 | 1 |
| 2 | 2 |
| 2 | 3 |
| 3 | 1 |
| 3 | 3 |
As you can see in my example above, place 3 doesn't offer course 2.
From here, you can simply query all of the courses available for a place by querying the place_id:
SELECT * from t_place_course WHERE place_id = 3
The above will return both courses 1 and 3.
You can optionally use a JOIN to get the other information about the course or place, such as the description:
SELECT `t_course`.`description`
FROM `t_course`
INNER JOIN `t_place_course`
ON `t_course`.`id` = `t_place_course`.`course_id`
INNER JOIN `t_place`
ON `t_place`.`id` = `place_id`
I've recently tried to create an executable with python 2.7 which can read a MySQL database.
The database (named 'montre') regroups two tables : patient and proto_1
Here is the content of those tables :
mysql> select * from proto_1;
+----+------------+---------------------+-------------+-------------------+-----
----------+----------+
| id | Nom_Montre | Date_Heure | Temperature | Pulsion_cardiaque | Taux
_oxy_sang | Humidite |
+----+------------+---------------------+-------------+-------------------+-----
----------+----------+
| 1 | montre_1 | 2017-11-27 19:33:25 | 22.30 | NULL |
NULL | NULL |
| 2 | montre_1 | 2017-11-27 19:45:12 | 22.52 | NULL |
NULL | NULL |
+----+------------+---------------------+-------------+-------------------+-----
----------+----------+
mysql> select * from patient;
+----+-----------+--------+------+------+---------------------+------------+----
----------+
| id | nom | prenom | sexe | age | date_naissance | Nom_Montre | com
mentaires |
+----+-----------+--------+------+------+---------------------+------------+----
----------+
| 2 | RICHEMONT | Robert | M | 37 | 1980-04-05 23:43:00 | montre_3 | ess
aye2 |
| 3 | PIERRET | Mandy | F | 22 | 1995-04-05 10:43:00 | montre_4 | ess
aye3 |
| 14 | PIEKARZ | Allan | M | 22 | 1995-06-01 10:32:56 | montre_1 | Hea
lthy man |
+----+-----------+--------+------+------+---------------------+------------+----
----------+
As I'm just used to code in C (no OOP), I didn't create class in the python project (shame on me...). But I managed, in two files, to create something (with mysql.connector) which can print (on the cmd) my database and excecute sub like looking-for() etc.
Now, I want to create a GUI for users with pyqt. Unfortunately, I saw that the structure is totally different, with class etc. But okay, I tried to go throught this and I've created a GUI which allows to display the table "patient". But I didn't manage (in the datasheet of QT) to find how I can use the programs I've already created to display. Neither how to display in a tableWidget only several rows of my table patient for exemple (Using QSQL).
For example, if I want to display all the table patient, I use this line (pyQt):
self.model.setTable("patient")
For this one, I got it, but that disturb me because there is no MySQL coding requisites to display my table and so I don't know how to sort only the rows we want to see and display them. If we only want to see, for example, the ID n°2, how to display in the table:widget only Robert ?
To recap, I want to know :
If I can take the coding I've created and combine it with pyQT
How to display (tableWidget) only rows which are selected by MySQL. Is that possible ?
Please find in the URL my code for a better understanding of my problem :
https://drive.google.com/file/d/1nxufjJfF17P5hN__CBEcvrbuHF-23aHN/view?usp=sharing
I hope I was clear, thank you all for your help !
I am trying to do multiple joins on the same MySQL table, but am not getting the results that I expect to get. Hopefully someone can point out my mistake(s).
Table 1 - cpe Table
|id | name
|----------
| 1 | cat
| 2 | dog
| 3 | mouse
| 4 | snake
-----------
Table 2 - AutoSelect
|id | name | cpe1_id | cpe2_id | cpe3_id |
|-----------------------------------------------
| 1 | user1 | 1 | 3 | 4 |
| 2 | user2 | 3 | 1 | 2 |
| 3 | user3 | 3 | 3 | 2 |
| 4 | user4 | 4 | 2 | 1 |
------------------------------------------------
I would like to see an output of
user1 | cat | mouse | snake |
user2 | mouse | snake | dog |
..etc
Here is what I have tried
SELECT * FROM AutoSelect
LEFT JOIN cpe ON
( cpe.id = AutoSelect.cpe1_id ) AND
( cpe.id = AutoSelect.cpe2_id ) AND
( cpe.id = AutoSelect.cpe3_id )
I get blank results. I thought i knew how to do these joins, but apparently when I'm trying to match cpe?_id with the name of the cpe table.
Thanks in advance for any assistance.
You need left join 3 times as well. Currently your query only joins 1 time with 3 critieria as to the join. This should do:
SELECT a.name, cpe1.name, cpe2.name, cpe3.name FROM AutoSelect as a
LEFT JOIN cpe as cpe1 ON ( cpe1.id = a.cpe1_id )
LEFT JOIN cpe as cpe2 ON ( cpe2.id = a.cpe2_id )
LEFT JOIN cpe as cpe3 ON ( cpe3.id = a.cpe3_id )
And you probably mean to INNER JOIN rather than LEFT JOIN unless NULL values are allowed in your AutoSelect table.
I think your design is wrong.
With tables like that, you get it the way it's meant to be in relational databases :
table 1 : animal
id name
1 cat
2 dog
3 mouse
4 snake
table 2 : user
|id | name |
|--------------
| 1 | user1 |
| 2 | user2 |
| 3 | user3 |
| 4 | user4 |
table 3 : association
|id_user | id_animal|
|--------------------
| 1 | 1 |
| 1 | 3 |
| 1 | 4 |
| 2 | 3 |
| 2 | 1 |
| 2 | 2 |
| 3 | 3 |
| 3 | 2
| 4 | 4 |
| 4 | 2 |
| 4 | 1 |
---------------------
Then :
select u.name, a.name from user u, animal a, association ass where ass.user_id = u.id and ass.animal_id = a.id;
In this case, your solution won't produce a good dynamic database. There are other ways to make combinations of multiple tables. I can show you by my own database what you should use and when you should use this solution. The scheme is in dutch, but you'll probably understand the keywords.
Like you, I had to combine my windmills with a kWh-meter, which has to measure the energyproduction of my windmills. What you should do, is this case, is making another table(in my case molenkWhlink). Make sure your tables are INNODB-types(for making Foreign keys). What I've done is combining my meters and mills by putting a pointer(a foreign key) of their ID(in Dutch Volgnummer) in the new table. An advantage you may not need, but I certainly did, is the fact I was able to extend the extra table with connection and disconnection info like Timestamps and metervalues when linking or unlinking. This makes your database way more dynamic.
In my case, I Also had a table for meassurements(metingoverzicht). As you can see in the scheme, I've got 2 lines going from Metingoverzicht to molenkwhlink. The reason for this is quite simple. All meassurements I take, will be saved in table Metingoverzicht. Daily meassurements(which are scheduled) will have a special boolean put on, but unscheduled meassurements, will also me saved here, with the bollean turned off. When switching meters, I need the endvalue from the leaving meter and the startvalue from the new meter, to calculate the value of todays eneryproduction. This is where your solution comes in and an extra table won't work. Usually, when you need just one value from another table a JOIN will be used. The problem in this case is, I've got 2 meassurementIDs in 1 link(1 for connecting and 1 for disconnecting). They both point to the same tablecolumn, because they both need to hold the same type of information. That is when you can use a double JOIN from one table towards the other. Because, both values will only be used once, and just needed to be saved in a different place to avoid having 1 action stored on different locations, which should always be avoided.
http://s1101.photobucket.com/user/Manuel_Barcelona/media/schemedatabase.jpg.html
I have a table which have category_id and parent_category_id. How I can get 1 category and 5 sub category by using SQL query.
Suppose table name is : Category
----------------------------------------------------------------
Category ID | Parent ID | Name
----------------------------------------------------------------
1 | NULL | Electronics
2 | 1 | Computer
3 | 1 | Calculator
4 | 1 | Mobile
5 | NULL | Four Wheeler
6 | 5 | Cars
7 | 5 | Trucks
8 | 5 | Jeep
9 | 5 | Van
Since MySQL does not support recursive queries/CTEs, you will have to emulate that (which is not, say, straightforward).
Here's an excellent tutorial on the subject:
http://explainextended.com/2009/03/17/hierarchical-queries-in-mysql/
I will have the decency of not copying the code here :)
For SQL Server, you can use the WITH query to get the complete path (more here http://msdn.microsoft.com/en-us/library/ms175972.aspx).
I have developed a website (PHP) that allow staffs to add records on to our system.
Staffs will be adding thousands of records into our database.
I need a way to keep track of what record have been done and the process/status of record.
Here a number of Teams I could think of:
Data Entry Team
Proof Reading Team
Admin Team
When staff (Data Entry Team) completed a record - he/she will then click on the Complete button. Then somehow it should asssign to 'Proof Reading Team' automatically.
A record need to be checked twice from a Proof Reading Team. If StaffB finish proof reading then another member from Proof Reading Team need to check it again.
When Proof reading is done, Admin Team will then assign "Record Completed"
In a few months later record might need to be updated (spelling mistake, price change, etc) - Admin might to assign record to Data entry team.
Is this good data entry management solution? How do I put this into Database Design perspective?
Here what I tried:
mysql> select * from records;
+----+------------+----------------------+
| id | name | address |
+----+------------+----------------------+
| 1 | Bill Gates | Text 1 Text Text 1 |
| 2 | Jobs Steve | Text 2 Text 2 Text 2 |
+----+------------+----------------------+
mysql> select * from staffs;
+----+-----------+-----------+---------------+
| id | username | password | group |
+----+-----------+-----------+---------------+
| 1 | admin1 | admin1 | admin |
| 2 | DEntryA | DEntryA | data_entry |
| 3 | DEntryB | DEntryB | data_entry |
| 4 | PReadingA | PReadingA | proof_reading |
| 5 | PReadingB | PReadingB | proof_reading |
+----+-----------+-----------+---------------+
mysql> select * from data_entry;
+----+------------+-----------+------------------------+
| id | records_id | staffs_id | record_status |
+----+------------+-----------+------------------------+
| 1 | 2 | 3 | data_entry_processiing |
| 2 | 2 | 3 | data_entry_completed |
| 3 | 2 | 4 | proof_read_processing |
| 4 | 2 | 4 | proof_read_completed |
| 5 | 2 | 5 | proof_read_processing |
| 6 | 2 | 5 | proof_read_completed |
+----+------------+-----------+------------------------+
Is there alternative better solution of database design?
i think design it's well done. but may be you want to separate group into groups table, and record_status into status table. If you're storing a lot of records you would store a lot of useless information, at least create an enum type for record_status field and group field
table: groups
id - name 1 - admin 2 - data_entry 3 - proof_reading
...
table: status
id - name 1 - data_entry_processing ...
and if you want the users to be in different groups at a time, you could create users_group table
table: user_groups
group_id - user_id 1 - 1 2 - 1 1 - 4 3 -
4 4 - 4 ....
Hope this helps