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I have the following entities in my system: COMPANY, POSITION, APPLICANTS. There is many to many relationships between POSITION and APPLICANTS, but the current model does not show that there is many to many relationships between COMPANY and APPLICANTS.
Does it make sense to you to have a join table foo that has the company_id, position_id and applicant_id or i should have a table that joins COMPANY and POSITION and another that joins POSITION and APPLICANTS?
I don't think so. You can get APPLICANT for a given COMPANY via JOIN with POSITION.
I think a relationship between a COMPANY and an individual becomes significant when they shift from APPLICANT to EMPLOYEE. I would not model it as you propose.
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I have 5 tables in my database called Employee, Company, Team, Locations and Position. Now Positions are assigned to employee on each of these levels i.e. to Company, Team and Location. To resolve this I have created 3 tables called CompanyPosition, TeamPosition and LocationPosition. An employee can hold multiple positions in each of these level i.e I can be a CEO, MD at company level etc.
Now I have a situation that in each of these position tables an employee can hold multiple positions and he will reports to someone holding multiple positions, but to only one of position at a time.
I am thinking of creating a new column called ReportstoPositionId in each of these tables CompanyPosition, TeamPosition and LocationPosition to solve this problem.
Can anyone suggest me that I am going in right direction or it can have some problem now or in furture.
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I have a couple of properties in my sql server SLS.Customer table which are references to other tables. I can't think of proper names for those tables. Help please :)
Table1: Contains the "How did you hear about us" values. (Example records: Through a friend, Advertisement, Seminar x, conference y, etc.)
Table2: Contains various reasons a customer refused to buy our product.
Table3: Contains the industry/business type a customer belongs to. (I thought of CustomerIndustry or just Industry but it sounds strange!!
Table4: Contains contact info of the person(s) related to a customer entity (specially if the customer is a company, rather than an individual, I need contact info of a person in charge). This is different from the tables PartyAddress and PartyPhones
As the question is suggestion based. I just put some suggestions here.
Table1:
RefererInfo
RefererDetails
Table2:
backlogReasons
backlogInfo
backlogDetails
Table3:
CustomerCategory
CustomerBackground
Table5:
PersonInChargeForParty
ContactsForParty
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I have 3 tables
Table1: Plant Table
PlantId(Primary key)
Plantname
and some other fields
Table2 :Inputfiles
Plantname,Filename
PlantId(foreign key) references PlantId(Plant)
Table 3; InputData
Id.
and other fields
I need to design it such a way that one plant can have many inpufiles So this is a 1-m between Plant Table and Inputfiles tables
Now when the user selects a inputfile from table2, all the data related to the input file is stored in Inputdata table3.
What should be the relation between table2(input files) and table3(inputdata)
Thank you
sun
A 1-1 relationship should exist between inputfiles and inputdata.
Based on your description of the problem, I would have inputfiles have the inputdata.id as a foreign key.
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I have 2 tables User and User_Event
User
id PK BIGINT
User_Event
event_id PK BIGINT
user_id FK References User.id
Should I create above tables before runtime
OR
should I create table "User_Event" for each Existing user at runtime (In this case table name would be like this
User_Event_user001,User_Event_user002....)
Now my questions is
1. Which design is better?
2. which implementation is faster?
For both questions, the best answer is to have an invariant database structure.
Modifying/creating the tables is a lot of work for databases, as they are designed for managing DATA inside the defined structures (tables, views).
It is very rare that changing the structure on the fly is pertinent, and even less effective.
--> create tables before runtime !
I don't know what is purpose of your system but classical implementation is to have one table User_Event and store data about all users in this table. If you want to get info for one user you should use query:
SELECT event_id FROM User_Event where user_id=<your user_id>;
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I'm looking for a little database design advice...
I have a spreadsheet with a few columns in it. Column 1 being a list of categories and the rest being related categories(to the category in column 1). I'm trying to figure out what the best way to setup the tables would be... My thought so far is to have a table that just lists the categories then have a table with 2 columns that holds the id of the category and the id of a related category.... Would this be the best way to do this? Any better ideas?
A self referencing table (parentId to childId) is how most people implement a hierarchical structure like the one you are describing.
Your way is the best. Academics would call it resolving a reflexive many-to-many relationship with an associative entity, but it's nothing more than what you described.
m:n relations should always (maybe there are exceptions) be made with extra table for relations. So it should be the most flexible solution