python (65.1k questions)

javascript (44.2k questions)

reactjs (22.7k questions)

java (20.8k questions)

c# (17.4k questions)

html (16.3k questions)

r (13.7k questions)

android (12.9k questions)

Questions - entity-relationship

DynamoDB : "Many-to-many" like relationship into a signle table

I'm trying to learn DynamoDB and i can't lie, i'm struggling to figure out best practice to make the named in relationalDB world "many-to-many relationship" between 2 tables into a single ta...
test-img

Panagiotis Giannelos

database

amazon-web-services

nosql

amazon-dynamodb

entity-relationship

Votes: 0

Answers: 1

Latest Answer

An adjacency list is the usual way this is addressed in DynamoDB. In this case you would store your driver and your car as items in the table and then you would also store a CarDriver that would hold ...
test-img

Michael Robellard

POJO within POJO, Entity-Relation problem

I have five tables in my database: AREA, AREA_TYPE, SAMPLE, PACK, UNIT @Entity(tableName = "AREA") data class AreaEntity( @PrimaryKey val id:String, val title:String, ...
test-img

rahman kalınbaçoğlu

android

android-room

entity-relationship

pojo

android-room-relation

Votes: 0

Answers: 2

Latest Answer

First the use of prefix, this is an option to circumvent the ambiguous column names (e.g. which id column is the correct one to use? (rhetorical)) BUT you would then have to play around with the queri...
test-img

MikeT

Need to redesign this ER Diagram

I want to design them drawing an ER Diagram. I have already designed an ER Diagram but teacher told me that it has only 5 entities and I need at least 7 or 8 entities. Also told me that I must not add...
test-img

beytullahdanis

database

entity-relationship

diagram

erd

Votes: 0

Answers: 1

Latest Answer

I think the answer to your diagram questions is right there in your entity list. You have an entity named MOVIE_DIRECTOR but in the diagram you have a relationship named DIRECTS. You just need to ch...
test-img

Kurt

Preserve data integrity in a database structure with two paths of association

I have this situation that is as simple as it is annoying. The requirements are Every item must have an associated category. Every item MAY be included in a set. Sets must be composed of items of t...
test-img

Gianluca Locri

mysql

database

database-design

relational-database

entity-relationship

Votes: 0

Answers: 2

Latest Answer

Interesting scenario. I don't see a slam-dunk 'best' approach. One consideration here is: what proportion of items are in sets vs attached only to categories? What you don't want is two fields on ite...
test-img

AntC

Posts

Questions

Blogs

Jobs