I have two tables with some same fields like:
Table A: fname, lname, address, age, email, mobile, website, blog
Table B: fname, lname, address, age, email
Both these tables are used by different modules on my website. I want to sync the first five fields of both tables in such a way that whenever a new row is added or an existing row is modified in Table A, the Table B is updated automatically and vice versa.
For Example.
A user created a new record in Table A. Now the Table B should also be updated with this new information. and vice versa if a user creates a new record in Table B, the Table A should also be updated with this new information.
A user modified a record in Table A. Now the Table B should also be updated with this modified information. and vice versa if a user modifies a new record in Table B, the Table A should also be updated with this modified information.
How can I achieve this. I thought of using triggers but would it not create an inifinite loop resulting is server error!
Is any field among those 5 guaranteed to be unique? You could add a conditional to the trigger to check to see if that field exists before inserting the record in the table.
You might want to rethink the design also. Storing duplicate records in 2 places seems a little scaring. You're going to have to have triggers for updates, inserts, and deletes.
If u just need to update one table in case the other table gets updated, Instead of creating a table (as a part of some other table), create a View which is also like a table but virtual (not real).
but since u've asked for both sides update.
What I believe is that you should go back little back of this problem....and tell us why u need to update both the tables according to the other table,,,
Because you are just keeping duplicate data at two places that is of no need.
So, try to think whether it can be done without creating two tables, or something like create one table and one view for partial columns requirement.
It is not an answer to your problem, but I am trying to solve your problem in an optimized way which is good for everyone's health....
Hope you understood what i tried to tell. :)
Related
I have a dashboard where I can update, delete and create. I have 3 separated tables, Developers, Absent, Date.
Developers contains developer names and personal information. Absent is used for a segment of code, basically on certain days someone is absent. Date is mostly the same but this is for holidays instead.
I joined tables, so absent.absent_id=developers.absent_id, date.date_id=developers.date_id
When I create a developer I need to insert values. HOWEVER, I'm having a problem. The IDs of the tables need to be manually inputed through the database. I would like it so that If I create a new developer on the dashboard using Insert, The absent_id and date_id are ID linked between tables.
In short:
If create developer on submit, Add new Auto-incremented ID row to all 3 tables. Anyway this can be done?
You can achieve it with 3 SQL request, first insert new Developer and return its ID, use that to insert a new row in Absent Table and also return its ID, use both IDs to create Date row, i don't think it's related to Front-end(React) but rather a backend.
Cheers.
I have learned more, and was compelled to find the solutions, mind changed.
PS dear experts, your help is appreciated in the time-saving nature of having forums and discussion in the first place, and also is mined for usefulness, not street cred. get helping or get off. The time I wasted reading posts where the answer was "I don't understand what you are trying to do..." and then questioning the OP with animus or incredulity, or suggesting some unrelated answer further confusing issues, is seemingly the problem with the world these days, if you want to help, help
Original Post:
Ok so as per the comments, thanks to ANYONE who volunteers any help with this problem.
I have a table and relationship design problem.
I have a table with a pk auto and I want to have a related table with a related column incrementally numbered that updates every time new data is entered in the form that is bound to it. It needs to update the related rows in the autonumbered table's key.
---the answer was to join the table on the autonumbered field.
The autonumber of the first table (main recordsource) is just an ID. I think I need two Primary Keys as I need to update the related record with that number in the entry form and move to NextRec but update the pk in the main table and move to NewRec , how do I join (see jpg image)?
I want enter results and update that existing record but update the adjoining pk so that a new record is created in the main table.
Tourney
more in depth:
From yours
My desired form
note that the calculation table feeds the upcoming games table, where a query shows the players recent results. I would like to split the upcoming results to show the players' recent game history, the second tab I would like to enter either one result or many results at a time. I hope I am clearer. You can see why I have had a challenge. See my form though. The recordsource is the upcominggames table and the data entry form is for input (ENTER GAME DATA)
-----the answer to this was an update query (a separate form) and then requery the statistics form to show the new matchups that were entered.
As from the comments, this is what I'm thinking of when I read your description:
Since the UpcomingGames will be entered first and exactly one GameResult can be entered per UpcomingGame, this will be a 1:1 relationship. As the name Upcoming says: The Upcoming data has to be entered before the Result can make sense. Unless an UpcomingGame can be cancelled, there will indeed be a Result for the Game, so there is no need to separate the information into 2 tables. I'd say, a user interface could look like this:
As you can see, the T_NUM column is an autovalue. Before entering any data, I initialized that column using a query like this (and deleted that record afterwards):
INSERT INTO Games ( T_NUM )
VALUES (1004);
This way, the numbering started with number 1005.
You won't be able to to avoid gaps in the numbering, as long as the users can remove existing records or cancel the insertion of a new record. If you want at least to avoid the latter, you will need some VBA code in the form.
I have a database with two tables. The first one contains the user_name, user_password, user_email. The second one contains the user_name, user_age, user_description.
When a person finds the user he needs by the user_name, the script looks through the database using the user_name, to give out the information about certain user.
But if the person changes his user_name via preferences, the value changes only in the first table.
Question:
1) Is there a way to make the user_name in the second table change automatically? (To connect them some how)
I am using MySQL (phpMyAdmin).
This is just a simple example. In "real world" I am trying to manage more serious applications that have more tables. Is there an easier way than to create a separate php query for each table?
You could always create an AFTER UPDATE MySQL trigger targeting single rows for this. See the manual. It's probably not easier than using separate PHP queries for the tables, though. You don't need to spell them all out, just map up what needs to be synchronized when, and abstract your code.
However I'd recommend that you use a unique ID field for the user and only store the username in one of the tables -- and refer to the user with the ID under the hood of your code, and in both tables. Not a good idea to use something changeable as a unique identifier in your database design.
The Situation:
So, on my website, I want to give users the opportunity to save complex sets of data from their excel tables. Since there will be a large number of users and limited resources, I don't want to store all the data in one single table.
My idea is to have tables where descriptive information is stored for the dataset the user wants to create. E.g.
Table: UserDatasets_sets
id, name, userid
Table: UserDatasets_columns
id, fk_UserDatasets_sets, name, type, length, etc...
And then at some place to run a mysql trigger that would
a) create a table of the name that is passed to be inserted with a certain prefix. E.g. 'UD_' + UserDatasets_sets.name and all the columns from the ..._columns table and an extra column fk_Acl.
b) Because I want to also give my users the opportunity to set permissions on the individual entries of their tables, I would then like to store a trigger for this newly created table. So that whenever a row is inserted, a corresponding row is created in the ACL table and the id is then set as the fk_Acl value on the user's table.
c) Last but not least, I would also like to store the same triggers in reverse, so that whenever a user deletes his dataset in the UserDatasets_sets table, the corresponding table gets deleted. The rest that is connected to this action could be deleted by cascading, right?
My Question:
Is this even possible to do as a trigger? (The reason why I would like to do this: I don't want to waste cpu and memory on running the more demanding php alternative.)
What would a query to store this trigger look like?
I've created a table name 'combined_data' using data from two tables 'store_data' and 'hd_data'. The two tables share a common column which I used to link the data when creating the new table and that is 'store_num'. What happens is when a user submits information to 'store_data' I want info from that submit such as store_num, store_name, etc to move into the 'combined_data' table as well as pull information from the 'hd_data' that pertains to the particular store_num entered such as region, division etc. Trying to come up with the structure to do this, I can fill in table names and column names just fine. Just curious if this is doable or if another solution should be sought out?
This is a common situation when saving data and requires to be split into 2 or more different repositories. I would create a stored procedure, and pass everything into a transaction, so if at any time something fails, it would roll back, and you would have consistency between your tables.
However, yes you can also do it with a trigger on insert of data on either store_data, or hd_data, if you would like to keep it simple.