Questions regarding usage of compound key (specific composite key) in database
Questions tagged [compound-key]
76 questions
3
votes
4 answers
Get aggregate sum of data by day and hour
The below is an example of the data I have.
date time size filename day.of.week
1 2015-01-16 5:36:12 1577 01162015053400.xml Friday
2 2015-01-16 5:38:09 2900 01162015053600.xml Friday
3 2015-01-16 5:40:09…
James White
- 535
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- 24
3
votes
1 answer
JPA compound key with foreign key and enum
Hi all,
Im trying to build all the jpa entities out of a legacy database. I have a recurrent problem: some "main" entities have a collection of "translations", where the primary key is the key of the "main" + the "language" identifier. Languages are…
landoooo
- 153
- 2
- 10
2
votes
2 answers
array_key_exists for compound key in array
How do I check to see if a compound key exists with array_key_exists such as
$myarr['ind1']['ind2']
Would like to see if the key ['ind1']['ind2'] exists in $myarr.
I googled this and looked at some similar answers but couldn't find anything.
macmiller
- 325
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2
votes
1 answer
How does MySQL handle compound unique indexes with limited lengths?
Assuming two columns in a MySQL (MyISAM) table:
title VARCHAR(1500)
url VARCHAR(155)
I want to create a composite unique index on both columns. I know of the limiting length feature for too long columns (like my title column). How does it play with…
Aufwind
- 25,310
- 38
- 109
- 154
2
votes
0 answers
mongodb compound keys duplicate key error
I'm facing a duplicate key error without finding a solution. I have a compound key created using the following command:
db.test.createIndex({"a":1,"b":1,"date":1},{unique:true})
then I inserted a document:
{
"a": "test_a",
"b":…
Karina Panucia
- 21
- 3
2
votes
2 answers
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 a workgroup.
Here are the relevant code snippets:
@Entity
@Table(name = "users_workgroup")
public class UsersWorkgroup…
egbokul
- 3,944
- 7
- 36
- 54
2
votes
1 answer
Why use a compound clustered key in Cassandra tables?
Why might one want to use a clustered index in a cassandra table?
For example; in a table like this:
CREATE TABLE blah (
key text,
a text,
b timestamp,
c double,
PRIMARY KEY ((key), a, b, c)
)
The clustered part is the a, b, c part of the…
user1529891
2
votes
1 answer
Cassandra cluster key usage
I'm banging my head on this, but, frankly speaking, my brains won't get it - or so it seems.
I have a column family that holds jobs for a rather large group of actors. It is a central job management and scheduling table that must be distributed and…
siliconchris
- 613
- 2
- 9
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2
votes
1 answer
Breeze.js: error when assigning compound foreign key with GUID and integer values
I'm encountering an error with Breeze.js version 1.4.12. I have an entity, OrderLine, that has a compound primary key consisting of one GUID field (OrderId) and one integer field (LineNumber). This entity has a self-referencing foreign key,…
aifdsc
- 21
- 1
2
votes
1 answer
CQL3 change primary key
Suppose I have a table of the following composition.
CREATE TABLE rollup (
hashname text,
key text,
day timestamp,
counter_value counter,
PRIMARY KEY (hashname, key, day)
) WITH
...
I want to run a query that looks like
SELECT * FROM…
Peter Klipfel
- 4,958
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2
votes
1 answer
creating a compound or composite key on google app engine
I have two models:
Car(ndb.Model) and Branch(ndb.Model) each with a key method.
@classmethod
def car_key(cls, company_name, car_registration_id):
if not (company_name.isalnum() and car_registration_id.isalnum()):
raise…
Rusty Rob
- 16,489
- 8
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2
votes
1 answer
SQL compound Key
I am trying to create a table that as a Primary Key uses Values from other tables.My lectures said that this is a compound key (Primary+Foreign) yet I can't seem to be able to find how to initiate one.Can someone try to explain this concept and how…
Theodore Sklavenitis
- 21
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2
votes
3 answers
Is it possible to (emulate?) AUTOINCREMENT on a compound-PK in Sqlite?
According to the SQLite docs, the only way to get an auto-increment column is on the primary key.
I need a compound primary key, but I also need auto-incrementing. Is there a way to achieve both of these in SQLite?
Relevant portion of my table as I…
Jonathan Hall
- 75,165
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1
vote
0 answers
Advanced JPA Mapping with Compound keys - OneToMany relationship
I am using JPA 1.0 and have following tables, namely, Type, Guide and Address (names simplified for clarity and highlighted in bold) It is a scenario, where in relationships between 3 tables is built on compound keys. Non key fields for every table…
user721025
- 172
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1
vote
1 answer
How can I create a model with compound foreign key?
anybody knows on how to create a model with compound foreign key to another model.
e.g.
UserInfo: userId, password, key, ...
GeoInfo: id, userId, password, storeName, ...
In the above sample models. Want to link GeoInfo to UserInfo using two fields…
eros
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