An XML file of the ORPHA codes, the coding system of rare diseases, is publicly available at the ORPHANET website as Orphanet_Nomencature_Pack_EN. I downloaded the English version and imported into R ...

In Codd's A Relational Model of Data for Large Shared Data Banks the following paragraph seems to be one of his justifications for the relational model: A lack of understanding of relational ...

I’m designing an Entity-Relationship diagram as the basis for a relational database. A timetable planner for a comprehensive school needs to decide, when creating a new lesson, whether the lesson is a ...

Why do I get this circular dependency error in NestJS TypeORM Relations with Entity Decorator when setting up a OneToMany and ManyToOne relation between User and Item? cannot access User before ...

I'm developing a FastAPI application, a file manager system, and I'm using PostgreSQL as the database. To define database entity models in my code, I previously used SQLAlchemy, but now I switched to ...

Let's have a data structured like this: users: [{ "name": "username1", "garages": [{ "name": "my one garage even though I may have several", ...

I need 1 record per Id and to achieve it I tried with self join, case statement as well tried using COALESCE function but I am still getting multiple records for same client. Below approach is mostly ...

From the book Fundamentals of Database Systems (7th edition) by Elmasri et al., pages 475-476: A multivalued dependency [MVD] X ↠ Y specified on relation schema R, where X and Y are both subsets of R,...

I have a many-to-many relationship between roles and permissions in my application. I already have the pivot table with columns role_id, permission_id, and a new column access_type with an enum that ...

I am using PostgresSQL 15 hosted by AWS Aurora serverless v2. I have a table includes 200 millions rows and I need to update a value on a column for all those rows. This table has primary key id which ...

Some relational databases only support savepoints and not nested transactions directly. So, what is the difference between both? Is one superset of other? I understand savepoints are not new ...

What does the # mean when placed before an attribute in a relational database schema? Umbrella(ID,Lido, Cost, Type) Lido(ID, Name, #Spots, Manager) Manager(FiscalCode, Name, Surname) Client(#Card, ...

I want to format plain query to hierarchy json to display on front-end but I don't know how I may have relational database that has Table called "Todo" which has following column ID Name ...

For example, I want to search for all rows that starts with \x00\xff\xaa in a binary data column. I am writing this pseudo-code in C# Entity Framework: IEnumerable<KeyValue> ...

I have 2 tables as below and I have a relational table. I want to access the details of an order. Which products were selected in the order and what is the quantity of the products. What should I ...