I have a linked table that contains descriptive information of restaurants such as name, address, city, etc.
tbl_Restaurant
REST_SITE_CD (PK)
Restaurant
Address
City
…
I have created a query based off of this linked table and a different table that hosts auditing information.
tbl_Audit
AuditID (PK)
REST_ID (FK)
Date
…
From this query, a form was created to allow the user to easily choose a restaurant by its name and location, and enter in the necessary auditing information.
However, some audited restaurants are not located inside tbl_Restaurants. I would like to manually enter these locations into the query, but the query does not allow me to enter new addresses that do not match an existing primary key in tbl_Restaurant.
The only solution I can think of is to create a redundant table just for unlisted restaurants and combine it with the query later on via a union query or something like that. However, I’m sure this violations a bunch of normalization principles. Additionally, it would be ideal if the custom locations are only reflected upon the query and not the linked table, if that makes any sense.
Any help would be appreciated! Please let me know if there’s any other information I can provide.
Records need to be stored in a table.
You can use a local table, and use a UNION ALL to add the records from your local table to the query. However, you can't enter them directly in the query, since union queries are not updateable. You need to add them to the table.
Related
We have a system with two main roles: service provider and customer. The provider side is users like doctors, nurses, and caregivers. The customer side is just the customer. all user types contain some common data and some uncommon data. in the current system, we have a table for each user type, and for common data, we have User table. currect system ERD is:
https://s4.uupload.ir/files/screenshot-20210710165449-1007x662_tpwd.png
in the current system, we have a lot of tables and we think about reducing them. our vision is to bring all user types in a single table called User and instead of a lot of tables, we have more columns. of course in some users, we have empty cells that do not belong to this user type.
I have 4 questions:
is it ok to bring customers and providers to a table like User?
what is the optimal number of columns in a table?
load a row with a lot of columns OR relation between different tables?
provider type should be a separate table or can be an enum?
It is best to put all users in single table. So when you check login there is less place to do mistake. When selecting user you dont need to use SELECT * FROM... You can use SELECT id, username, name FROM...
Dont put too many columns, if there is some data which you dont need when searching or displaying users, you can create helper table "user_meta" with dolumns user_id, meta_key, value where user_id and meta_key are primary key
Answered by first 2 answers
Provider type should be enum if there will not bee needs to expand with additional types.
I have been working on a database design and I'm stuck hitting a wall. I'm ending up with what I'm reading is not a normalized database structure but I'm having issues trying to find a "more correct" design and if this design is acceptable how do I execute it in Access?
TLDR: If a table with a single column set as an auto number is an acceptable design, how do you go about inserting a record in it using Access?
The segment of the database of concern is creating a structure for storing companies. Requirements for this is that any changes need to be approved by another user and all historical changes need to be captured so that it can be easily reverted also a company can have multiple aliases but only one legal name.
There is three tables in my solution but one of them is a single column table. From what I've read 95% of people on stack overflow all think its a very bad idea but I've found one post were people are that there are cases for it. I think this is not normal also because I can't find a way to just create a new record in a table with only an auto number column (In Access I have not tried others yet).
Table Structure
Company Names : ID, Company ID, Is Legal Name, Created By, Created On, Approved On, Approved By, Event ID, Is Active
(A company could have a few different names known to the public: TD vs Toronto Dominion. Each name is inserted here with a reference to the company it belongs to)
Companies : ID (Auto Number)
(A company exists and this is its ID)
Companies History : ID, Company ID, Market ID, Holding Company ID, Created By, Created On, Approved On, Approved By, Event ID, Is Active
(These are the historical changes that have been made to the company and who did them and who approved them)
Column Notes:
Event ID : is a FK reference to a table holding each record of actions that have either created, updated or deleted records. (User Research using method [y], Typo Fix, ...)
Is Active : Since deleting records is not possible (historical records need to be kept) this column is used to track if this record is to be included in queries.
Options I see and their issues:
I could get rid of the companies table and make Companies History : ID be the new company id but I find that in that case each time I want to update a company I would need to update each FK reference to the previous company id (I don't think this would be a very normalized approach)
Another Option I see is that I get rid of Companies table and use Company Names : ID as the company id and I would add a column to Company Names called Alias of Company ID. I find that solution adds a log of complexity to my stored data where an alias has company information that differs from the entry that was aliased.
Another Option is that I could add the columns: Created By, Created On, Approved On, Approved By, Event ID and Is Active but this would be duplicating information found in the first record for this company in the Companies History table and this isn't adding any real description to this record.
Anther Option is that I make the Companies table a mirror of Companies History and that when I update or insert a record in Companies I would also insert a record Companies History. With this solution I find that again I duplicate information, that newest record in "Companies History" would hold the same information found in last Inserted or Updated record in in Companies
Another option but is to replace the Companies : ID auto number with a short text and I just get the hash of the current timestamp + a random int. I can now insert new records into this table using access but I feel that this is overkill since I just need the exact same functionality as the auto number.
Another option is move only the legal name into Companies table but now when the legal name of a company changes I have no way of tracking this. Also if I want a list of all names I need to use a union on Companies and Company Names. I find that using unions can reduce performances of queries and I use them only when explicitly needed.
If I don't want to duplicate any information and I don't want to update all FK it seems that I need a table with a single column. If this is acceptable how do I go about inserting a record into a table with a single column set to auto number in Access.
If Companies can be derived from CompanyNames (select distinct CompanyId from CompanyNames), there is no point storing again that information. Just replace that table by a view if you want it (but it as little added value).
On the other hand, if CreatedOn refers to the Company creation (not the row creation) then it is obviously a property of the Company, and I would rather work with
Companies --> Aliases.
But of course I don't know the ins and outs of the reality you're dealing with.
I've been doing some reading on 'one to many' databases but I'm struggling understand the best way to implement a solution in my case.
I want a MySQL database to record which employees have read certain training hand-outs at work.
So I have a table of Employees. And I have a table of Hand-outs.
I want to record if the Employee has clicked to say they've read the hand-out.
My Employee table has ID, Name, Email.
My Hand-out table has ID, Title
Am I better adding a field to the Employee table that will contain a list of "Hand-out IDs" to show which hand-outs they've read?
I need to be able to easily search to show what percentage of Employees have read a particular hand-out and I think my method would make that very difficult?
I can't have separate fields on the Employee table such as Handout1, Handout2 etc as new hand-outs will be added regularly.
I'm sure this must be a common problem so wondered if someone could direct me to the best solution for this?
Thanks
I think you need a bridge table here which records relationships between employee and hand-out records. Something like this:
Employee_Handout (ID, EmployeeID, HandoutID)
Every time a new handout comes out, you would insert a record into the handout table. Then, when a given employee reads that handout, you would insert a new record into the Employee_Handout table. You probably don't need to persist non-reads, since they could easily be detected as being absent from the bridge table.
The primary key for this column would probably be (EmployeeID, HandoutID), assuming you would only want a single record relating an employee reading a given handout. This would also mean that a given employee/handout relationship could only be persisted once.
I hope someone can help me with this:
I have a simple query combining a list of names and basic details with another table containing more specific information. Some names will necessarily appear more than once and arbitrary distinctions like "John Smith 1" and "John Smith 2" are not an option, so I have been using an autonumber to keep the records distinct.
The problem is that my query is creating two records for each name that appears more than once. For example, there are two clients named 'Sophoan', each with a different id number, and the query has picked up each one twice resulting in four records (in total there are 122 records when there should only be 102). 'Unique values' is set to 'yes'.
I've researched as much as I can and am completely stuck. I've tried to tinker with sql but it always comes back with errors, I presume because there are too many fields in the query.
What am I missing? Or is a query the wrong approach and I need to find another way to combine my tables?
Project in detail: I'm building a database for a charity which has two main activities: social work and training. The database is to record their client information and the results of their interactions with clients (issues they asked for help with, results of training workshops etc.). Some clients will cross over between activities which the organisation wants to track, hence all registered clients go into one list and individual tables spin of that to collect data for each specific activity the client takes part in. This query is supposed to be my solution for combining these tables for data entry by the user.
At present I have the following tables:
AllList (master list of client names and basic contact info; 'Social Work Register' and 'Participant Register' join to this table by
'Name')
Social Work Register (list of social work clients with full details
of each case)
Social Work Follow-up Table (used when staff call social work clients
to see how their issue is progressing; the register has too many
columns to hold this as well; joined to Register by 'Client Name')
Participants Register (list of clients for training and details of
which workshops they were attended and why they were absent if they
missed a session)
Individual workshop tables x14 (each workshop includes a test and
these tables records the clients answers and their score for each
individual test; there will be more than 20 of these when the
database is finished; all joined to the 'Participants Register' by
'Participant Name')
Queries:
Participant Overview Query (links the attendance data from the 'Register' with the grading data from each Workshop to present a read-only
overview; this one seems to work perfectly)
Social Work Query (non-functional; intended to link the 'Client
Register' to the 'AllList' for data entry so that when a new client
is registered it creates a new record in both tables, with the
records matched together)
Participant Query (not yet attempted; as above, intended to link the
'Participant Register' to the 'AllList' for data entry)
BUT I realised that queries can't be used for data entry, so this approach seems to be a dead end. I have had some success with using subforms for data entry but I'm not sure if it's the best way.
So, what I'm basically hoping to achieve is a way to input the same data to two tables simultaneously (for new records) and have the resulting records matched together (for new entries to existing records). But it needs to be possible for the same name to appear more than once as a unique record (e.g. three individuals named John Smith).
[N.B. There are more tables that store secondary information but aren't relevant to the issue as they are not and will not be linked to any other tables.]
I realised that queries can't be used for data entry
Actually, non-complex queries are usually editable as long as the table whose data you want to edit remains 'at the core' of the query. Access applies a number of factors to determine if a query is editable or not.
Most of the time, it's fairly easy to figure out why a query has become non-editable.
Ask yourself the question: if I edit that data, how will Access ensure that exactly that data will be updated, without ambiguity?
If your tables have defined primary keys and these are part of your query, and if there are no grouping, calculated fields (fields that use some function to change or test the value of that field), or complex joins, then the query should remain editable.
You can read more about that here:
How to troubleshoot errors that may occur when you update data in Access queries and in Access forms
Dealing with Non-Updateable Microsoft Access Queries and the Use of Temporary Tables.
So, what I'm basically hoping to achieve is a way to input the same data to two tables simultaneously (for new records) and have the resulting records matched together (for new entries to existing records). But it needs to be possible for the same name to appear more than once as a unique record (e.g. three individuals named John Smith).
This remark actually proves that you have design issues in your database.
A basic tenet of Database Design is to remove redundancy as much as possible. One of the reasons is actually to avoid having to update the same data in multiple places.
Another remark: you are using the Client's name as a Natural Key. Frankly, it is not a very good idea. Generally, you want to make sure that what constitutes a Primary key for a table is reliably unique over time.
Using people's names is generally the wrong choice because:
people change name, for instance in many cultures, women change their family name after they get married.
There could also have been a typo when entering the name and now it can be hard to correct it if that data is used as a Foreign Key all in different tables.
as your database grows, you are likely to end up with some people having the same name, creating conflicts, or forcing the user to make changes to that name so it doesn't create a duplicate.
The best way to enforce uniqueness of records in a table is to use the default AutoNumber ID field proposed by Access when you create a new table. This is called a Surrogate key.
It's not mean to be edited, changed or even displayed to the user. It's sole purpose is to allow the primary key of a table to be unique and non-changing over time, so it can reliably be used as a way to reference a record from one table to another (if a table needs to refer to a particular record, it will contain a field that will hold that ID. That field is called a Foreign Key).
The names you have for your tables are not precise enough: think of each table as an Entity holding related data.
The fact that you have a table called AllList means that its purpose isn't that well-thought of; it sounds like a catch-all rather than a carefully crafted entity.
Instead, if this is your list of clients, then simply call it Client. Each record of that table holds the information for a single client (whether to use plural or singular is up to you, just stick to your choice though, being consistent is hugely important).
Instead of using the client's name as a key, create an ID field, an Autonumber, and set it as Primary Key.
Let's also rename the "Social Work Register", which holds the Client's cases, simply as ClientCase. That relationship seems clear from your description of the table but it's not clear in the table name itself (by the way, I know Access allows spaces in table and field names, but it's a really bad idea to use them if you care at least a little bit about the future of your work).
In that, create a ClientID Number field (a Foreign Key) that will hold the related Client's ID in the ClientCase table.
You don't talk about the relationship between a Client and its Cases. This is another area where you must be clear: how many cases can a single Client have?
At most 1 Case ? (0 or 1 Case)
exactly 1 Case?
at least one Case? (1 or more Cases)
any number of Cases? (0 or more Cases)
Knowing this is important for selecting the right type of JOIN in your queries. It's a crucial part of the design assumptions when building your database.
For instance, in the most general case, assuming that a Client can have 0 or more cases, you could have a report that displays the Client's Name and the number of cases related to them like this:
SELECT Client.Name,
Count(ClientCase.ID) AS CountOfCases
FROM Client
LEFT JOIN ClientCase
ON Client.ID = ClienCase.ClientID
GROUP BY Client.Name
You've described your basic design a bit more, but that's not enough. Show us the actual table structures and the SQL of the queries you tried. From the description you give, it's hard to really understand the actual details of the design and to tell you why it fails and how to make it work.
I'm designing a database for my boss in which he wants a list of every dental surgery within a certain area, with every dentist at said surgery listed.
What would be the best way to go about this?
I'm leaning towards having a seperate table that contains only dentist names, since having them all in one table would get overcrowded/confusing.
The only problem with this is that he wants to be able to look at the screen and see everything laid out in this format:
Dental Practice_________Dentist name__________ Address________Phone number_______etc
____________________________Dentist name
____________________________Dentist name
_________________________Dentist name
Can this be achieved in table view or would I have to create two separate tables and link them together on a report to show him?
Store the addresses in one table, store the names in another table, create a junction table to show which dentist belongs with which address. create a form to show the information. You will need the junction table, because I think you will find that some dentists operate from more than one address.
Address table
AddressID
etc
Dentists
DentistID
etc
DentistAddresses
AddressID
DentistID
As long as your tables are properly indexed, you can create a query that will form the basis of the form to show the data. You should also consider subforms, the layout you illustrate is a form/subform set-up in MS Access. The address would be in the main form and the dentist list in the subform, which would be based on the junction table.
Just be very careful about changing addresses. The user cannot edit address, they must create a new address.
Well, what you will need is a single table that lists areas.
Table:
Areas
- AreaID
- AreaName
and a table for the Dentists which references the Areas Table by FOREIGN KEY
Dentists:
- DetistID
- DentistName
- DetistContactNumber
- AreaID
This will allow you to write a query something like
SELECT *
FROM Dentists d INNER JOIN
Areas a ON d.AreaID = a.AreaID
to retrieve the results you are looking for.