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“No Loop” Constraint for hierarchical data in postgresql

I've got table like this in postgres: id primary key parent_id foreign key on id some data columns I need no a constrain which prevents cycles on the parent relations. There might be more tree in ...
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What's the best method to implement a very large tree structure in a database?

I am writing a back-end program for a trading brokerage with 1000+ clients, some of which make as many as 500+ trades a day. My C# program keeps track of everything in the following tree method: The ...
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MySql - Get all child categories until not exists

Based on this answer, can you please tell me what's wrong in the next code ? I'm trying to get all child categories. The example that I try it is: DELIMITER $$ DROP FUNCTION IF EXISTS ...
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0answers
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B Tree and B+Tree diferencies

I'm studying B+ Tree and B Tree and I would like to understand two things about it, if someone can clarify it to me I would appreciate: Why can I store more search keys on an B+ Tree Index? My guess ...
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0answers
101 views

Building a tree in Apache Derby 10.10

I know this question has been asked probably a million times, so please forgive me asking it again. I am not a DBA and have very little knowledge of SQL and Derby, but need some kind of a solution as ...
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82 views

MySQL: Hierarchical query to get the direct and indirect child

I am just trying to modify the code as in MySQL: Tree-Hierarchical query to get values inside single quotes and seems like the system hangs. Not sure where I am going wrong.. Here is the code. BEGIN ...
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82 views

How can I use PostgreSQL's partial sum tree index (if it even exists)? Do any databases allow for use of such an index?

GiST (Generalized Search Tree) indexing is an advanced system which brings together a wide array of different sorting and searching algorithms including B-tree, B+-tree, R-tree, partial sum trees, ...
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188 views

How to represent group by in relational algebra

I have to plan a plan tree based on relational algebra.My question is that at some point I have a SORT ORDER BY the output of a join, so how do you represent group by in relational algebra.