Top "Compound-key" questions

Questions regarding usage of compound key (specific composite key) in database

SQLite table constraint - unique on multiple columns

I can find syntax "charts" on this on the SQLite website, but no examples and my code is crashing. I …

sqlite unique-constraint compound-key
dplyr issues when using group_by(multiple variables)

I want to start using dplyr in place of ddply but I can't get a handle on how it works (…

r group-by dplyr compound-key
How to merge two dataframes using multiple columns as key?

Say I have the following dataframes: DF1 <- data.frame("A" = rep(c("A","B"), 18), "B" = rep(c("C","…

r merge dataframe compound-key
Compound/Composite primary/unique key with Django

How can you create models (and thus tables) with a compound (composite) primary/unique key using Django?

database django django-models many-to-many compound-key
Map with multiple keys in C++

I want to store data by both, their name and their index. In other words, I want to map string …

c++ key std stdmap compound-key
In a junction table, should I use a Primary key and a unique constraint, or a compound/composite key?

I have read through handfuls of what would seem to make this a duplicate question. But reading through all of …

sql-server tsql compound-key
JPA Compound key with @EmbeddedId

In a legacy database, I have three tables: Users, Workgroups, and UsersWorkgroup. UsersWorkgroup stores what role a user has in …

java jpa jpa-2.0 compound-key
Can not set java.lang.Integer field id to org.hibernate.id.IdentifierGeneratorHelper

I need to store some data in a MySQL-database using Jpa 2/Hibernate 3.5.1. For legacy reasons the table I want to …

mysql hibernate jpa compound-key