I have control dashboard where multiple tables are listed with query
And in dashboard I can switch it to one table from ALLData to User1Table... and vice versa.
When there is only one table chosed I can easily manipulate data. However, I am struggling with updating rows when ALLData(all tables) are listed in dashboard. I can update it checking each table. I was wondering is there any better way to update it.
Tables have no DR. All tables have same column names.
//ALLData
SELECT * FROM users1
UNION ALL
SELECT * FROM users2...
user1
id name tel status
1 Bob 911 1
user2
id name tel status
3 Anna 11 0
3 Jack 12 1
//ALLData in dashboard
id name tel status
1 Bob 911 1
3 Anna 11 0
3 Jack 12 1
I can use id and status as PK
Related
The context :
I have these three simple SQL tables : my database diagram
a Request has one or N Request_Field
Request_Field is a pivot table
Value inside the pivot table Request_Field can sometimes contain dates in string format
a Field has 0 or N Request_Field
These tables are part of a greater database and I cannot change them at the moment.
My question :
Is it possible to query multiple "Request" and order them by a specific value in "Request_Field" ?
Example :
Request table
id
1
2
3
Request_Field table
id
request_id
field_id
value
1
1
1
John
2
1
2
2021-01-01
3
2
1
Jane
4
2
2
2020-01-01
5
3
1
Jack
6
3
2
2022-01-01
Field table
id
label
1
name
2
desired_date
The SQL query I try to make : get all Request ordered by the desired_date record of the Field table (DESC).
Request desired results
id
3
1
2
Thank you
I know this is probably so odd to ask. But lets say I have 3 tables:
Table 1
ID
Name
1
Adam
2
David
3
Conor
Table 2
ID
Name
1
Adam
2
Derek
3
Niall
Table 3
ID
Name
1
Adam
2
David
3
John
Is there any way I can write a query to get the unique names across all 3 tables. So it would return "Adam, David, Conor, Derek, Niall, John"
Order doesn't matter
If it helps, all name values are related to a names table
yes , one way is to union them
select name from table1
union
select name from table2
union
select name from table3
union automatically removes duplicate cases
I'm building a e-Commerce platform (PHP + MySQL) and I want to add a attribute (feature) to products, the ability to specify (enable/disable) the selling status for specific city.
Here are simplified tables:
cities
id name
==========
1 Roma
2 Berlin
3 Paris
4 London
products
id name cities
==================
1 TV 1,2,4
2 Phone 1,3,4
3 Book 1,2,3,4
4 Guitar 3
In this simple example is easy to query (using FIND_IN_SET or LIKE) to check the availability of product for specific city.
This is OK for 4 city in this example or even 100 cities but will be practical for a large number of cities and for very large number of products?
For better "performance" or better database design should I add another table to table to JOIN in query (productid, cityid, status) ?
availability
id productid cityid status
=============================
1 1 1 1
2 1 2 1
3 1 4 1
4 2 1 1
5 2 3 1
6 2 4 1
7 3 1 1
8 3 2 1
9 3 3 1
10 3 4 1
11 4 3 1
For better "performance" or better database design should I add
another table
YES definitely you should create another table to hold that information likewise you posted rather storing in , separated list which is against Normalization concept. Also, there is no way you can gain better performance when you try to JOIN and find out the details pf products available in which cities.
At any point in time if you want to get back a comma separated list like 1,2,4 of values then you can do a GROUP BY productid and use GROUP_CONCAT(cityid) to get the same.
Maybe it's because I don't understand how to search for the right verbiage, but I'm having difficulty understanding how to attach multiple users to a table with multiple columns.
Here is what I'm attempting to do:
table name: user
user_id user_name
1 abc
2 xyz
3 pqr
4 new
table2 name : brackets
id user_id bracket_name
1 4,2 bracket_1
2 4,3,1 bracket_2
3 2,1 bracket_3
4 3,4,2 bracket_4
-- OR --
table name: user
user_id user_name brackets_id
1 abc 2,3
2 xyz 1,3,4
3 pqr 2,4
4 new 1,2,4
table2 name : brackets
brackets_id user_id bracket_name
1 4,2 bracket_1
2 4,3,1 bracket_2
3 2,1 bracket_3
4 3,4,2 bracket_4
I'm using nodejs and sequalize as my ORM and understand enough to read, write, delete and update to these tables, but when it comes to organizing my data, I'm completely lost!
Is it possible to add an array to MYSQL with the user ID's or the brackets that the user is allowed to access? The bracket are generated by a user and then they can invite their friends to join a bracket. Users can join multiple brackets and join other brackets as users.
Any guidance would be very helpful!
I think a Junction Table would simplify this for you: http://en.wikipedia.org/wiki/Junction_table
It would look something like:
table name: user
user_id user_name
1 abc
2 xyz
3 pqr
4 new
table2 name : brackets
brackets_id bracket_name
1 bracket_1
2 bracket_2
3 bracket_3
4 bracket_4
table3 your junction table:
user_id brackets_id
1 2
1 3
2 1
2 3
2 4
etc.etc.
The tables are for users to access different places
The design as below:
user table:
<user>
userid
username
place (the row define access rights)
place table:
<place>
placeid
placename
floor
My thoughts:
three places and placeid are 001,002,003
one user and userid is 001 to aceess these three places
<user>
userid username place
001 john 001,002,003
<place>
placeid placename floor
001 A 1
002 B 2
003 C 3
004 D 4
My question is,
in "user" table, the attribute "place" contains many placeids,
and separate by a comma, this design is fine or bad ?
It needs to separate the place values from "user" table ?
Using a comma delimited list to do a many to many relationship is bad design. You should use an intermediate table instead:
<user>
userid
username
<place>
placeid
placename
floor
<accessrights>
userid
placeid
Instead of putting "1,2,3" in user.place for userid 001, then, you put three rows in accessrights, all with userid 001 and one with each placeid.
That's not a good idea. Make a separate table to store the relationship:
<users-places>
userid placeid
1 1
1 2
1 3
Indexing your approach would not be straight forward - although possible.
Use the name "users-places" as it implies what 2 tables it relates. Change the name if you significantly store more information about this relationship - ie, you start adding columns to this new table.
Also, name your tables in the plural form. Singular is reserved for class names. Tables are thought of as collections.
Thank you all,
I modified my design as below, is it fine ?
<user>
userid username groupid
1 john 1
<group>
groupid groupname
1 admin
2 general
3 special
<group_manage>
groupno groupid placeid
1 1 1
2 1 2
3 1 3
4 1 4
5 2 1
6 2 2
7 2 3
<place>
placeid placename floor
1 A 1
2 B 2
3 C 3
4 D 4