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Questions tagged [rdbms]

A relational database management system (RDBMS) is a database management system (DBMS) in which data is stored in tables and the relationships among the data are also stored in tables.

A relational database management system (RDBMS) is a database management system () that is based on the relational model as introduced by E. F. Codd, of IBM's San Jose Research Laboratory. Many popular databases that are currently in use are based on the relational database model.

RDBMSs have become a predominant choice for the storage of information in new databases used for financial records, manufacturing and logistical information, personnel data, and much more. Relational databases have often replaced legacy hierarchical databases and network databases because they are easier to understand and use. However, relational databases have been challenged by object databases, which were introduced in an attempt to address the object-relational impedance mismatch in relational database, and XML databases.

History:
The development for the RDBMS model began at in 1974
The first commercially available RDBMS system was in 1979
The first RDBMS system for Mac OS was in 1984

References:

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Complex Ranking in SQL (Teradata)

I have a peculiar problem at hand. I need to rank in the following manner: Each ID gets a new rank. rank #1 is assigned to the ID with the lowest date. However, the subsequent dates for that particular ID can be higher but they will get the…
Satyabrat Sahoo
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Do RDBs like MySQL and PostgreSQL store copy of data for each index? Or just B-tree with links to real objects?

How RDBs like MySQL and PostgreSQL manage memory for new indexes? My guess that RDB creates B-tree (or other indexes) with References/Links to real objects in memory. Another guess that it duplicates all the data for each new index. So basically…
Игорь Кравченко
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How to transfer table from one database to another database?

I was working on Azure Data Studio. By mistake I created a table in the system administrator's database. I want to transfer it to another database which is created by me. How can I transfer that table?
Shruti Agrawal
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Database metadata table design

I'm working on a blog website with an Admin Panel. It consists of Articles, Categories, Tags, and Updates tables. The updates is a meta-data table which tracks any updates in any other table. What is the best way to link the updates to the others?…
Go3shom
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Querying with Subquery and Joins- Giving different results on the same table -- MySQL

I am trying to query this table: https://www.w3resource.com/mysql-exercises/subquery-exercises/find-the-names-of-the-employees-who-have-a-manager-who-works-for-a-department-based-in-united-states.php the question is: Write a query to find the name…
nonsensical_coder
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Allow different subjects same year, but not same subjects different years

I'm creating a SQL table to record information on subjects taken by students. I have a constraint which is the students are allowed to take multiple subjects in the same year, but are not allowed to same subjects over different years. For example,…
RofyRafy
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Indirect duplication of a foreign key?

Suppose, I have three tables named Table user, team, task user user_id team_id team team_id task task_id user_id team_id where the User table references team_id then a task table references the user_id and…
Garri Sumalapao Farol
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Postgres copy table schema is_null constraints not included

i have a table with the ff columns and constraints : create table newtable( id int4 not null primary key, lastname varchar(50) not null, firstname varchar(50) not null, middlename varchar(50) not null ) I'm developing a workflow…
zysirhc
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fibonacci series program using functions in pl/sql

I've to create a function which print the Fibonacci series as its result. I've used a varray in the program below but it is giving me an error saying "PLS-00201: identifier 'ARRAY' must be declared" on line no. 2. create function fibonacci7(x…
Shashwat Shukla
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How to find types of dependencies in the given relational schema?

Consider a mobile store application designed for the customers to buy mobiles of their choice. The store has various models of mobiles. Every mobile is identified with a unique mobileid. Every model has a different batterylife and cost. Here is a…
Gayatri Barhate
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SQL query from multiple tables and fetching data

I have the following tables which are represented in form of schema : Customer (cid, cname, mobile, address, gender, email) Orders (order_no, company_name, order_date, cid, item_id, quantity) Items (item_id, item_name, unit_price) E_company…
Goru Chagol
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Can I use the same foreign key in multiple child tables from the parent table in XAMPP phpmyadmin?

The books are academic and do not specify what to do with the foreign keys. For the college assignment I am building an SQL database for a dental clinic. If I had to create foreign keys, do I need one per table or can a table specialist dental…
SpagettiCode
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How to apply Oracle VPD Policy to restrict update some specific columns?

I have some problems when trying to solve my homework about VPD Policy of Oracle. The question is "MYADMIN account has the right to select and update students' Enroll Information. But he is not allowed to see the Score of the student's Enroll…
Orange Pumpkin
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When using Dapper to return an Entity, should I specify the column list?

Which do you prefer and why? db.Query("Select * from Students").ToList(); or db.Query("Select Id, FirstName, LastName, Address, Age, Etc From Students").ToList();
NPearson
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Why is Redis used as an RDBMS cache when an RDBMS also has it's own cache?

Ok this maybe a silly question to you, but really please... i don't understand: Why is Redis used as an RDBMS cache when an RDBMS also has it's own cache? Both Redis and RDBMS is on the same server, or possibly even the same data center local area…
user1034912
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