Questions tagged [inheritance]

For questions about extending a base object's features into a derived object.

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11
votes
2answers
2k views

Conceptual ERD Multi-table many to many, or possibly recursive?

I'm creating a conceptual diagram [yes, I know I've included attributes and keys - but this is just for me to consolidate what I'm doing whilst learning] -- so please treat it as Conceptual with the ...
10
votes
5answers
52k views

Insert into select into multiple related tables using INSERT_IDENTITY

Okay setting the scene. I have three tables, (Table1, Table2 and DataTable) and I want to insert into Table1 and Table2 using DataTable as source. So for every row in DataTable I want a row in Table1 ...
7
votes
1answer
4k views

Performance issues with inherited tables and indices

I have a PostgreSQL database with a master table and 2 child tables. My master table: CREATE TABLE test ( id serial PRIMARY KEY, date timestamp without time zone ); CREATE INDEX ON test(...
6
votes
1answer
2k views

Index is not used with table inheritance

I have a PostgreSQL 9.0.12 database with a master table and 2 child tables. My tables: CREATE TABLE test2 ( id serial PRIMARY KEY, coll character varying(15), ts timestamp without time ...
6
votes
1answer
576 views

PostgreSQL and table inheritance

I'm not sure if this is the right place for this, so please feel free to tell me if it is off-topic or there is a better place to post. I am working on a fantasy sports based project, and the number ...
5
votes
3answers
6k views

Using table inheritance instead of mapping tables

This seems like a pretty common scenario: several types that all compose the same child type. This could typically look like so: -- 'name' is unique per parent record CREATE TABLE sometype ( ...
5
votes
2answers
9k views

Query parent table and get child tables columns

I have two tables, one inherits the other: CREATE TABLE parent ( col1 INTEGER ); CREATE TABLE child ( col2 INTEGER ) INHERITS( parent ); // Insert some data INSERT INTO parent( col1 ) ...
5
votes
2answers
766 views

Postgresql inheritance based database design

I'm developing a simple babysitter application that has 2 types of users: a 'Parent' and the 'Babysitter'. I'm using postgresql as my database but I'm having trouble working out my database design. ...
5
votes
1answer
2k views

Transfer row from 'parent' to 'child' without creating duplicate and without knowing all 'parent' columns

I want to set up a database with different schemas that correspond to different data-entry systems. There needs to be a “master” (administration) schema with a “parties” table, and multiple other ...
4
votes
2answers
10k views

How to drop inheritance?

I am new to PostgreSQL. The situation I have is someone created a child table inherits from the parent table. And dropped the child table. But the parent table still has the "down arrow" sign on it. ...
4
votes
2answers
2k views

Abstract classes in SQL Server. Are they even possible?

I have a very specific question that I am surprised no one has yet asked. It involves a concrete class model and SQL Server 2016 DDL. The main point is: In my model, some classes inherit from a base ...
4
votes
1answer
7k views

Best practise for polymorphic associations in MySQL

I have a MySQL database with 3 tables holding the main classes of data: companies (company_id) persons (person_id, company_id) loans (loan_id, company_id) Both a 'loan' and a 'person' belong ...
4
votes
1answer
3k views

Polymorphic Association - is it bad? [duplicate]

In the following schema: Collections Upvotes Reports Upvotes Reviews Upvotes I'm tempted to have a single Upvotes table with a single "entityId" column that stores either the CollectionId, ...
4
votes
2answers
1k views

How to enforce data consistency across one-to-one relationship in an inheritance hierarchy

Consider this design for a typical school database: Person: ----------------- FirstName LastName SocialSecurityNumber Phone Email Student: ----------------- Grade Teacher: ----------------- ...
3
votes
1answer
2k views

What is the purpose of “Schema Owner”?

If I create a new schema and set the schema owner to another schema, for example dbo, what is the meaning of that in regards to my new schema? Does my new schema inherit the same permissions from it'...
3
votes
1answer
2k views

Enhanced ER Model Supertype / Subtype modeling issue with inheritance and recursion

Before posting, I have looked for a good solution on internet and I have coined this post for 3 days in row and trying to think through it prior this post. So if I have missed something or got it ...
3
votes
2answers
5k views

Partial unique constraint spanning multiple tables in postgres

To enforce partial uniqueness in postgres, it is a well known workaround to create a partial unique index instead of an explicit constraint, like so: CREATE TABLE possession ( possession_id serial ...
3
votes
1answer
418 views

Is this a step in the right direction for normalization? SQL 'inheritance' and Many-to-Many relationships

Context: So, this is kind of a compound question, but they go together, and definitely wouldn't make sense split up into separate questions. I've been working on a new database for what will end up ...
3
votes
1answer
855 views

Inheritance or lot of relationship?

I have to transpose a class Diagram into a Physical Data Model (more precisely MySQL database structure). In my class diagram, I have a lot of entities (A, B, C, D) which inherit from an other entity,...
2
votes
1answer
2k views

Postgres 9.5 foreign table inheritance not using indexes

In PostgreSQL 9.5.0 I have a partitioned table that collects data by months. I tried to use the new PostgreSQL feature of foreign table inheritance and pushed one month of data to another PostgreSQL ...
2
votes
3answers
390 views

Record inheritance in mySQL

I have been struggling with this for a little while. I want to have a set of calendar records. The top level will apply to a large group; the next level will apply to a sub-set and the final level ...
2
votes
1answer
232 views

Inheritance of “dictionary tables”

(In case this matters: I'm using SQLite) My silly little database has a surprising number of tables with identical structure: CREATE TABLE GTag ( ID INTEGER PRIMARY KEY NOT NULL, ...
2
votes
1answer
639 views

Database relationship inheritance [closed]

I have a vehicle sales store. In my store I sale many kind of vehicles for example cars and boats. And I would like to keep track of the sales. My vehicles has some attributes as: Arrive on store ...
2
votes
2answers
2k views

Postgres inherit from one role and not another

I'm a little new with postgres but have a decent understanding of roles. What I have are users that inherit from their normal "data_analyst" group. This group is used to manage all data analyst users ...
2
votes
1answer
61 views

Finding a good DB design for my project

I've posted this on stackOverflow but this might be a more suitable place. I'm really struggling to find a good DB design for my project using SQL server. I've already implemented a few models which ...
2
votes
1answer
142 views

Correct way to join row in parent table to row in one of several children tables

I have a parent table product, and several children tables like phone, tablet, smartwatch etc. The parent and children have 1-1 relationship. This means that for every row in parent table, there will ...
2
votes
2answers
348 views

Dimensional Model for inheritance in dimensions

How are dimensions typically modeled in a dimensional model if one dimension logically inherits from another dimension? For example, assume I have an Employee dimension and a Driver dimension, where ...
2
votes
0answers
71 views

Is it possible to drop inheritance from the parent table (top down)?

Our system uses inheritance on two levels: master child_level_1 child_level_2 child_level_2 child_level_2 child_level_1 child_level_2 child_level_2 child_level_1 child_level_2 The idea was to ...
2
votes
0answers
442 views

Is it correct to model a specialized table using a foreign key whose referencing attributes are not also forming its primary key?

In the process of designing a database model, I would like to implement a Class Table Inheritance pattern in a way that does not seem common at first. I would like to know if it is a correct ...
2
votes
0answers
173 views

PostgreSQL database re-design considerations

We have a 2TB PostgreSQL database, which contains two groups of tables that account for about 90% of the storage used. These two groups can be loosely described as 2 big tables partitioned, the first ...
2
votes
1answer
142 views

Designing an extensible authentication system

I need to design an authentication system, where different type of authentication schemes may exist. At the end, I should assign a passphrase (access token) to the user. I have several authentication ...
1
vote
2answers
783 views

Views that inherit a table and syntax in PostgreSQL

I am getting a syntax error but don't understand what is wrong. I am using a reference here. This is my sql-snippet: CREATE OR REPLACE VIEW stipa_test.stipa_view AS ( SELECT * FROM ... ...
1
vote
1answer
2k views

Cannot add or change records

I'm designing a database structure wherein I like to apply the concept of inheritance. There's a base tables and derived tables in which the relationship is one-to-one. I'm quite new as of how could ...
1
vote
2answers
40 views

Deleting rows from child table without deleting from parent [closed]

I have 2 tables, connected with inheritance. I want to delete some rows from the child table. The deletion part works but it deletes rows from the parent as well: CREATE OR REPLACE FUNCTION ...
1
vote
1answer
119 views

Improve PostgreSQL SELECT performance in a parent table (inheritance)

I have a PostgreSQL 9.2 database where each account has a schema, like below: My_Database |-> Schemas |-> AccountA |-> AccountB |-> AccountC |-> AccountD |-> ...
1
vote
1answer
143 views

Can I improve the way pg_dump exports inherited tables?

Given a postgresql 12 database with some table inheritance, and the child table adds no additional columns: CREATE TABLE parent ( id integer NOT NULL PRIMARY KEY, name text NOT NULL ); ...
1
vote
1answer
259 views

user security inheritance in SQL Server 2016

I'd like to build a bunch of new databases (several dozen) in SQL Server 2016. However, I'd like all users to access a single database (called SECURITY for now), and apply security to that one ...
1
vote
1answer
335 views

Will switching from Concrete Table Inheritance to Single Table Inheritance improve the performance of my queries?

I currently have an application that allows people to view and share 10 different types of posts (ex SportsPost, WorldNewsPost, TechnologyPost, etc). All posts types are conceptually the same, but ...
1
vote
2answers
132 views

Oracle MV requires object type to be defined as FINAL?

I want to create an Oracle 18c materialized view (MV) on a table that has a user-defined datatype called ST_GEOMETRY: The MV would do a COMPLETE refresh on a schedule — on a local table. Some info ...
1
vote
0answers
516 views

Implementing a graph-like design on postgresql using CTEs and inheritance

This question is about attempting to model/design an elementary graph-like database within postgres. The starting point is that graphs have: Nodes Nodes have properties Node are connected by (bi/...
1
vote
0answers
812 views

PostgreSQL doesn't use index on inherited tables

I have two tables in PostgreSQL 9.4.5 deployed on Amazon RDS: an append only, weekly partitioned, All Positions table. These store all position readings from about 100,000 sensors. There are about 50 ...
1
vote
0answers
270 views

Alter schema of Access 2013 database with linked table

I'm trying to change the schema of an Access 2013 table. I want to lengthen some of the text fields. When I change the schema and try to save I get dialog with Operation is not supported for this type ...
0
votes
3answers
3k views

Can i have one foreign key to both parent and it's childs in postgresql?

I want to have a foreign key to reference table and it's children. Here's how I tried and failed: CREATE TABLE parent ( id serial, CONSTRAINT parent_pk PRIMARY KEY(id) ); CREATE TABLE child ( ...
0
votes
2answers
31 views

Why does selecting an attribute of an Oracle object require an alias?

My GIS software has an Oracle 18c object type called ST_GEOMETRY. The object type has attributes: The attributes of the spatial type represent the following information: Entity: The type of ...
0
votes
1answer
240 views

Postgres role does not inherit permissions from its member role

I want to group my postgres database permissions to set of roles and then assign users to these parent roles to manage all permissions from a central place. I created a role called admins and granted ...
0
votes
1answer
49 views

Inheritence and Primary Key Constraints

I am currently trying to see how the object oriented features come in play in Postgres. During a few tests I noticed that when you insert in or delete from inheriting tables that those changes also ...
0
votes
1answer
163 views

Progressive child tables scan in PostgreSQL?

We have append-only events table where events from different devices are being collected. We use PostgreSQL 9.6 and pg_partman to split the table into monthly partitions. Data is partitioned using ...
0
votes
2answers
121 views

Inheritance of unknown type at creation time

Say I have a table called People into which people are inserted from the moment they are born. Now lets say I want some subclasses of people based on their job. So there are also tables for Plumber, ...
0
votes
1answer
1k views

Inheritance discriminator column better int or varchar or enum?

What is the best practice for storing a discriminator column ? Does it make any difference ? Any pros/cons of using one over the other ? I am using MySql with Entity Framework but the question goes ...
0
votes
1answer
545 views

Foreign key double inheritance SQLITE

I'm designing a domotic system database and I'm trying to figure out how to represent two foreign keys. This is the cardinality I want. Consider 1...N Areas (rooms, halls, kitchens, etc.): Area 1 - ...