user (table)
userid
groupid
.
group (table)
groupid
ownerid
.
such a design from the ER diagram, each of the two tables has a 1-to-N connection to the other.
does such a design need to be optimized?
if a user belongs to only one group, then the user can mark an attribute as whether the group leader or not.
if a user belongs to more than one group, then the group records the group leader information and saves the corresponding user id,. This is only one-to-one.
one-to-many, definitely not.
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as shown in the figure, a simple add and query operation takes up to 1 second [environment: windows + python3 + django2]. (the amount of data in PS: is not much, and todo_list has only 2 rows of data, which is still so slow.) def get(request): -...
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designing a complete project includes not only the front-end project design, but also the need to build local servers and databases. As a front-end developer, what kind of database should you choose? There are a lot of people around who are using mongodb...
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2018-04-10T08:26:03.830775Z 0 [Note] usr sbin mysqld (mysqld 5.7.20) starting as process 9836 ... 2018-04-10T08:26:03.923709Z 0 [Note] InnoDB: PUNCH HOLE support available 2018-04-10T08:26:03.923741Z 0 [Note] InnoDB: Mutexes and rw_locks use GCC atomic b...
Table T_USER T_ROLE : the following is the table creation and data script drop table if exists T_USER; CREATE TABLE T_USER( USER_ID INT, USER_NAME VARCHAR(25) ); INSERT INTO T_USER VALUES(1, USER_A ); INSERT INTO T_USER VALUES(2, USER_B )...
what databases are used by app with a very large amount of data, such as facebook, Weibo, Jinri Toutiao and so on? how to ensure access speed? ...
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mongoose What is the reason for ? ...
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first of all, I found a lot of database design on Baidu, it can be said that there are different opinions! I see an intermediate table is designed like this, commodity ID sku attributes, unit price inventory, see that the intermediate attributes store js...