Questions tagged [hierarchy]

For issues relating to arranging items into ordered levels.

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CTE get all descendants with parents

Schema: CREATE TABLE item ( id int primary key, parent_id int, FOREIGN KEY(parent_id) REFERENCES item(id) ); INSERT INTO item (id, parent_id) VALUES (1, NULL), (2, 1), ...
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Database for dynamic number of hierarchy levels

My client wants to support dozens of cities where each city has its own graph-like data structure to store location hierarchy, for example: City 1: Region -> District -> Street -> Shop City ...
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How to map child (leaf-level) nodes to specific parents with/without ltree for aggregations?

What would be the best way to aggregate across hierarchies? I am using Postgres and have the following 3 tables (folder, folder_hierarchies, and work) - folder Column Type Description folder_id (pk)...
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Determine hierarchy with SELECT on same table twice

I need to model a hierarchial relationship in a mysql database. I found an excellent article, here, which describes the nested set model. I managed to adapt this work for my own requirements and it'...
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1 vote
1 answer
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Query hierarchical file permissions

I have a table representing some files with their paths and another table with file sharings by user and files. Below is Table files, simplified. Example: I have a directory A (path /A) containing ...
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2 votes
1 answer
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Is there any harm in storing other rows' int PKs in a hierarchyID instead of an arbitrary number?

I'm looking at common uses of hierarchyID, and most examples use some sort of arbitrary numbering for the HID nodes: HID, Name /, World /1/, USA /1/1/, Texas /1/1/1/, Houston /1/1/2/, San Antonio /1/2/...
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1 vote
1 answer
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What facilities of SQLServer would help achieve a goal of tracking a hierarchy over time?

I've a requirement to create a system that tracks what is essentially a hierarchy of containers over a period of time, modelling a supply chain. Everything in the chain is a container, so the process ...
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2 votes
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MS-SQL and HierarchyID

I have been using HierarchyID for the last 2 years in some of my tables for obvious purposes And I have kept a Column (int) for the last node number for example if I have these rows so the int column ...
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Postgres ltree: Get all accessable resources by groups and sub groups

Have following Data scheme: Roles: Each role has either a resource assigned or a resource_group. A user wich has a role on a group has also access to all resources that are within the group or within ...
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1 answer
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MSSQL Merge 3 hierarchy tables

I want to merge 3 hierarchy tables into one table. The 3 tables: CREATE TABLE dbo.tbl1 ( key1 varchar(50) NULL, key2 varchar(50) NULL ) ON PRIMARY CREATE TABLE dbo.tbl2 ( key2 varchar(50) ...
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1 vote
3 answers
137 views

Constraint to prevent immediate loop in hierarchy

I have a companies table: CREATE TABLE companies ( id bigserial, name varchar(255) NOT NULL PRIMARY KEY (id) ) I want companies to have parents and childs. A company might have many parent and ...
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2 votes
1 answer
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Recursively find the path to all leaves descending from a given parent in a tree

I'm trying to write a query to identify the path to each furthest descendant of a particular parent node in a table of tree structures like: 0 1 | | 2 3 | | 4 5 ...
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2 votes
1 answer
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Org chart CTE with exact index but plan shows expensive sort node

I've got a moderately large table (148 million rows) that's got pretty common org chart attributes to it. Names are changed, but it's the same idea. I was thinking of adding a hierarchyid column to ...
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3 votes
1 answer
69 views

Ordering CONNECT BY siblings

I have an hierarchical query that uses CONNECT BY: select wonum, parent, classification, classstructureid, division, worktype, status, glaccount, fircode, ...
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1 vote
1 answer
60 views

Relationship design for areas, managers and general manager

Given some specifications I need to design a database for an organization. One of the parts has to do with areas. In the organization there are different areas, each area has a boss, and there is also ...
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1 answer
59 views

How to improve poor performance with two joined CTE expressions on hierarchical data?

I have a table of hierarchical data where I want to select entries that, 1) only include matches that are descendants of a given parent, and 2) returns the full hierarchical path of the matched ...
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Recursively list dependencies / references of a stored procedure

I'm trying to import a subset of our production dump with impdp for our local development database running on Oracle XE. To find out what other objects I have to import for a particular stored ...
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1 answer
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Aggregating nested set models with field constraints

I have a table built on the nested set model that basically records transactions of different natures (defined by the field idx): pk lft rgt idx value 1 1 30 2783 20402.710000 2 ...
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9 votes
1 answer
317 views

Find friends of friends (recursively) efficiently using Postgresql

Objective: Users submit their Contact Books, and then the application looks for connections between users, according to their Phone Number. Something like "6 Handshakes" idea (https://en....
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1 vote
2 answers
623 views

Hierarchical data using closure table, how to ensure that a column is unique within the parent node?

I store hierarchical data in a Node-table, combined with a closure table (NodeClosure). Each node has a column "name" that should be unique among the sibling nodes (link to parent-Node + ...
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2 votes
3 answers
302 views

Foreign key reference to column that is no primary key

I know, foreign keys should uniquely identify rows and therefore reference a primary key. However, consider my example: There are 4 pre-defined categories, and for some combinations of values for ...
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1 answer
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Pattern for copying hierarchical data from one table to another?

Imagine a table with three columns: an ID primary key, a nullable ParentID referencing the ID column on that same table, and a TreeID to indicating the records that make up a particular tree. A basic ...
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-1 votes
1 answer
150 views

SQL Variables inside SELECT query in a function

MariaDB 10.3.14 I have a function that generates the root id in a hierarchy: The function is this: CREATE FUNCTION `getRootId`(GivenID INT) RETURNS int(11) DETERMINISTIC BEGIN DECLARE ch INT; ...
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-1 votes
1 answer
105 views

MS SQL 2017: hierarchy tree - get quantity of last level components

There's a table of items with their components. Components depth vary i.e. some items may have one level of components other may have tens nested components. I need to get quantinty of last level ...
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1 vote
1 answer
56 views

Generate hierarchical path

I have a classstructure table: create table classstructure (classstructureid number(8,0), classificationid varchar2(25), parent number(8,0)); insert into classstructure(classstructureid, ...
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1 vote
1 answer
184 views

Database Design - hierarchical structure

We are trying to redesign a database that currently holds thousands of parameters for different datatypes and currently has a flat data structure. We generate XML files from the database, which our ...
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0 votes
1 answer
20 views

Is there such a thing as an OLAP cube that can change the number of levels in a hierarchy without having to be rebuilt?

The current analytics solution that my team works with cannot handle changes in the structure of one of its hierarchies. If a new level or branch is added, then the entire domain must be first backed ...
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0 answers
44 views

How to retrieve all children of a parent record?

I have one MySQL table with this columns: id father son street city I want to obtain all descendants of a father recorded, how I can do this? I tried this: WITH RECURSIVE filhos AS ( select login, ...
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963 views

Sql subquery for nested parent child data

I have two tables , on parent table (categories ) and child table (features).. I have this query select c.* , (select GROUP_CONCAT(f.featuresId , f.featuresTitle ) from ...
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2 votes
1 answer
95 views

How to select id of father from the child id recursively

I have in the field cod_categorizacao_pai the ID of the father, and I need to mount a select that just enter an ID and it will list the paternal IDs of this ID until it reaches the parent of all. How ...
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2 votes
1 answer
2k views

How to query all entities associated with all children (recursive) of a node in SQL?

This question is about SQL in general. Answering specifically for MySQL would be helpful but not necessary. Ok, I’m having trouble putting this into words… so bear with me. Say I have a tree of ...
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1 vote
0 answers
261 views

Worked example of closure tables with from and thru dates

I work for a law enforcement agency, and have been asked to create a way of storing the chain of command in such a way that its structure can be viewed at any point in time, not only as it is now. ...
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3 votes
2 answers
3k views

SQL Server CTE Bottom to Top Recursive with Where clause

I have an Employee Table with an EmployeeId, ManagerId and a Name field. The goal is to make a recursive With fetching all the rows from an employee to the top manager (ManagerId is null). I found ...
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4 votes
3 answers
70 views

How can I pass on a value in the hierarchy based on the value of the parent using an hierarchial query?

I have a table with categories and another table with a discount for categories per user: create table category ( id NUMBER NOT NULL, parent_id NUMBER, name nvarchar2(255), PRIMARY KEY( id) )...
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0 votes
1 answer
348 views

Advantages of a hierarchical schema for private chat

This post claims that All modern chatting interfaces, without exception, implement a hierarchical and a not-chronological schema for chat. It also links another post which gives an example ...
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3 votes
2 answers
3k views

Parent Child Relation in same Table . Select Query to get only parent records and Records not comes under parent child relation

I have a table with Parent-Child Relation in the same Table. Some Sample Data id │ name │ parent │ is_active ════╪══════════════════════╪════════╪═══════════ 1 │ Company A ...
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3 votes
1 answer
1k views

How to do hierarchical queries without CTE tables or recusive queries in Snowflake? (parent, child relationships)

I have several tables in Postgres that we are migrating to Snowflake. Some of these table are hierarchical (a foreign key point to the same table), normally to query this data I use CTE tables and/or ...
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1 vote
1 answer
1k views

Oracle hierarchical query: aggregate over each node's descendants, give results in tree pre-order

Given hierarchical data, for each item I need to get the sum of a column over the sub-tree rooted at the item, and I need the results in pre-order. Example: for the data employee_id | manager_id | ...
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  • 233
2 votes
1 answer
1k views

How make recursive json on mysql

my table looks like CREATE TABLE `test_comments` ( `id` int(10) unsigned NOT NULL AUTO_INCREMENT, `parent_id` int(10) unsigned DEFAULT NULL, `test_id` int(10) unsigned NOT NULL, `user_id` int(...
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1 vote
0 answers
377 views

How to get the hierarchy of particular employee using JPA spring boot?

I am trying to find a way to get the employee hierarchy in an organization using JPA and Spring boot. The problem is similar to the following link Similar Data Model If A reports to B and B reports ...
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2 votes
0 answers
52 views

Design for a child to have a single parent `A` OR `B` with FK cascade constraint?

I'm assuming this is not possible with PK and FK... Let's say I have tables A, B, and C. A and B are "parents", and B and C are "children" A is the root B can be the child of either A or B C ...
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1 vote
0 answers
74 views

Scalable way to manage aggregated statistics over time in hierarchy?

I'm using a closure table (Postgres through Django) to roll up stats through a hierarchical tree. When a node that is 10 layers deep has a value that increases, each parent's sum total of that value ...
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-2 votes
2 answers
118 views

What's the best way to represent an event from a system in a chat?

Conversations -------------- id Messages -------------- id conversation_id user_id reply_to_id content created_at I was looking at this question and I had a question: How to build a table for a ...
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1 vote
0 answers
62 views

Nested set model in higher dimensions

The nested set structure is well-known and involves using left and right values to denote the relative heirarchy of nodes on one axis. Is there a generalization of this structure to higher dimensions?...
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8 votes
3 answers
23k views

Parent/Child Relationship Table Design - What's The Best Practice?

I have a single table for storing 'Tasks'. A task can be a parent and/or a child. I use the 'ParentID' as the FK referencing the PK on the same table. It is NULLABLE, so if it is NULL it does not have ...
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  • 503
2 votes
1 answer
183 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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1 vote
1 answer
46 views

How to add foreign key in a table where column value can come from two different tables?

I have three tables create table main_comments ( id serial primary key, comment text not null ); create table sub_comments ( id serial primary key, main_id integer not null, comment ...
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  • 113
3 votes
2 answers
625 views

Get all descendants from 3 hierarchical tables

I have the following tables within a database: +-------------+ +-------------+-------------+ +---------------------------+ | project1 | | project2 + | project3 ...
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0 votes
1 answer
325 views

Bypass truncated data type error in `CREATE TABLE AS`

I am attempting to recreate the code from this excellent tutorial in MariaDB 10.2 to try and build nested sets from an existing adjacency list. (The goal being to ingest changes to the adjacency list ...
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3 votes
2 answers
71 views

Nullable, dependent attributes

I'm designing a database for students. Computer science students here in Switzerland can decide between different specializations, e.g. application development, system engineering etc. There are ...
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