Questions tagged [inheritance]

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

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23 views

Poor performance in a SELECT using Inheritance

I will detail my problem in good detail. I have a marketplace application so I make a decision to make a multitenant per schema approach. I like this approach because of the isolation of data, but I'm ...
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1answer
34 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 ...
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1answer
20 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 ...
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1answer
35 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 |-> ...
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1answer
428 views

Django Multi Table Inheritance and Preserving Child and Child History

Place can have many different one to one fields, that’s why it can have bookstore, restaurant, and hardware store. But can the same place be both a bookstore and a restaurant at the same time? Now if ...
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1answer
5k 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 ...
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1answer
125 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 ...
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1answer
2k views

Inheritance and foreign keys in Postgres

This is about using inheritance and foreign keys in Postgresql databases. Consider the following simplistic example whose structure is based on what I am building at the moment (but the specifics were ...
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1answer
115 views

Can Postgres inherited tables overlap

Is it possible to have single row in a parent table be visible in more than one inherited (child) table? Perhaps by inserting a row directly into the master table and then "making it visible" in one ...
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1answer
19 views

PostgreSQL 10.6: Alter parent table will block ALL children?

I want to add a column to near 74.000 child tables. These tables continually have insertions and reads from all the services in the company, in almost realtime. If I add a column to the parent table, ...
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19 views

I have multiple different objects which share most attributes, but vary on a few, what methods could I use to model them?

I have a few different items which mostly share the same attributes, but then have a few extra/less. In OOP they could be modeled well with inheritance, but postgres' inheritance is limiting and doesn'...
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1answer
63 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 ); ...
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1answer
27 views

Table Partitioning Using Inheritance and Triggers

I am trying to do table partitioning in PostgreSQL using inheritance and triggers but the problem that have occured to me is that the data does not move from the parent table to the children tables I ...
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1answer
15 views

Pass information to another table with the same inherit

Suppose the following scenario ... I have two tables (A, B) that inherit from a Z table, the SGBD is postgresql, these tables do not have an additional column, my question is how to pass a row from ...
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1answer
392 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'...
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11 views

Tables are switching when switching inheritance

I have two tables 'jobs' and 'jobs_history' and for some reason 'jobs' inherites from 'jobs_history'. I want to change the inheritance such that 'jobs_history' inherites from 'jobs'. Since the columns ...
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0answers
33 views

Single metadata base table in Postgres

I am a fan of adding timestamps to tables in the form of created_at, updated_at and deleted_at. But it can be tedious to add these fields to every table. I was wondering, is it a bad design decision ...
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1answer
244 views

PostgreSQL Trigger to override insert on table with inheritance

We have a table documents that is partitioned by time into child tables like documents_2019_01, documents_2019_02. We do this using a BEFORE trigger on the parent documents table to insert into the ...
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1answer
98 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 ...
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2answers
180 views

DB model strategy to override field value

We have to store some dynamic configuration in JSON format in DB. There would be some default configuration, and it can be overriden per account. Can someone help me with the strategy to store such ...
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1answer
41 views

make exist table as inherit

i try to create parent table for exists table, by next algorithm: -- CREATE TABLE CREATE TABLE t1 (id serial PRIMARY KEY); CREATE TABLE foreign_t1 (id serial, t1_id integer REFERENCES t1 (id)); -- ...
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2answers
673 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 ... ...
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0answers
62 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 ...
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1answer
331 views

Altering a parent table in Postgresql 8.4 breaks child table defaults

The problem: In Postgresql, if table temp_person_two inherits fromtemp_person, default column values on the child table are ignored if the parent table is altered. How to replicate: First, create ...
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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 ...
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1answer
1k 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 ...
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1answer
125 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 ...
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0answers
392 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/...
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2answers
303 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 ...
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0answers
335 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 ...
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1answer
426 views

How to list all the inherited tables from the parent table?

I have 3 tables (janitor, security & manager) which inherited from the user table. What is the query can be used to produce the following result(list all the name of the child tables)? Thank you....
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1answer
158 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 ...
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3answers
5k 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 ( ...
2
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1answer
531 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 ...
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0answers
147 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 ...
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1answer
2k views

PostgreSQL: Multiple Inheritance tables (one child to two parents)

If I have a base table and 2 or more tables that inherit from it, child1 and child2, I can insert a record into a child table and it shows up in base as you would expect. However what I want to know ...
2
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1answer
208 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, ...
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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 ...
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0answers
269 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 ...
2
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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
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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 ...
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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, ...
5
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2answers
673 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. ...
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2answers
642 views

Modeling a product database and dealing with inheritance

So, to get better at designing databases, I'm attempting to model a database system after the AR15 Builder. Here is what I have so far: While it makes sense logically, I'm afraid there may be ...
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1answer
222 views

Is it possible to set order in which inherited tables a scanned in postgresql?

I have a postgresql measurement table which is partitioned based on logdate column by month. Suppose I have city_id integer column and want to select latest row with city_id = 125. When I run explain ...
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3answers
321 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 ...
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0answers
732 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 ...
4
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2answers
7k 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 ) ...
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5answers
51k 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 ...
3
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2answers
4k 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 ...