what should I do logically if I want to set the top (charge) while publishing information (free, charging)? How can the data table be designed properly? Has not been clear about the train of thought, hope that experienced gods to give guidance. which ...
there are two table-building schemes that I have come up with: first: order_id order id shop_id merchant id goods_id goods id . this way is to write all kinds of id in the order table and associate them when needed. second: order_id order id s...
in actual projects, customers often clap their heads and decide to add and delete some status fields. take a chestnut, for example, to publish an article, the initial status status field has only two, one is the "unpublished " status, and the other is ...
Export the relational schema diagram through the ER diagram, remember to underline the primary key and use the arrows from the reference pattern to the reference pattern to indicate foreign key constraints. wants to know if there is no difference betwee...
at present, if you encounter such a problem of using mysql, first describe the scenario (some simplifications have been made to facilitate the answer): now there are two machines that use the same database account and access and operate a mysql addres...
problem description has a relationship to manage: has multiple app, multiple tags per app, tag, multiple user per tag. User may be under tag11 or tag12 of app1, or under tag21 or tag22 of app2. how to establish a relational table in this case? add...
I am currently working on the design of a database table for a data management system, but I have encountered such a situation: for example, there are two types of data, one is grouping group, the other is member member; , and then each group has a lo...
the company has built a Spring Cloud micro-service framework and now wants to provide a micro-service interface for executing sql statements. the question now is how to design better: 1. The interface parameters should contain the sql statement to be e...
when designing an attachment storage table for a system, do you use decentralized storage of information to each required table? Or do you centrally store the attachment information in a table and then associate it in the table you need to use? Or are t...
HTML <? while ($row = mysqli_fetch_array($permission_data)){?> <tr> <td class="manager"><?=$row[ name ];?>< td> <td class="manager"> <i...
for example, there is an option list at the top reports Statistics articles goods Manager Edit Statistics this is the name of each title each title can enter a different face for example, managers can enter the above four facets editing ca...
want to ask a question see what everyone does suppose there is an item < 1 the user sets up a list after buying item A, and uses the relational database to find 1 and then go to the information table product to introduce purchased goods suppose one...
is there a book to improve abstraction in designing database tables according to requirements? ...
recently, I m going to do a Mini Game. When it comes to the achievement system for the first time, I read some materials and make a whole table by myself, but I don t like it. I always feel strange. Please give me some advice. first of all, ach...
explore the following example: 1. Background: A system faces 2 objects and has the following permissions users: you can pay bills, apply for invoices, and apply for refunds Administrator: you can agree to apply and invoice the user, and you can ...
in development, there are some scenarios where we need to store information for a time period in the database. For example, an event has a start time and an end time, and we can store it in the database with two fields such as startDate and endDate. But...
like Wechat s comments on friends, when checking moments, the friend s name will show the name of the comment, and the name of the comment will also be the name of the comment. ...
1. How to decompose (A, B)-> E, (C, D)-> E, A-> C, C-> An into BCNF,? 2, U = (Agraine Brecinct C pyrrhene E) F = {B-> Greco ce-> Breco C-> Areco B-> Dle le C-> D}. Decompose into BCNF? 3. The BCNF decomposition that I understand at present is to fin...
(the mobile version can t upload the picture, go back to make it up tonight) General uid. If the figure above is a string of fixed-length numbers, how is it generated? When storing uid in a database, doesn t it usually start at 1 and then grow itsel...
our company wants to set up a financial reconciliation system because of the rise in business, and then give it to me to design. data currently available: sales orders and bank flows. requires reconciliation once a month to check whether the customer...