Questions tagged [relational-database]

A relational database is a digital database based on the relational model of data. This model organizes data into one or more tables (or "relations") of columns and rows

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Database design with performance issue and use of views

I am designing database for a school system. I am having to create a lot of tables and a lot of link tables to maintain a structure in the system. I am trying to maintain foreign integrity and trying ...
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Does this Relational Database Model make sense?

Here is a flat version of my datamodel. It is sensor readings for various data acquisition equipment. https://i1295.photobucket.com/albums/b628/colnewman26/Work%20Screen%20Shots/...
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Are there any benefits in not having referential integrity keys in database?

So Referential integrity is good, but are there scenarios where not having constraints is better? For example when all the logic of relationships is kept in code? or when the database upgrade is ...
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1answer
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How to define item level permissions in a relational database

I need to model a database design to provide item level permissions to users based on the user's role access. I am using asp.net with sql server 2012 I am looking at similar experience on how ...
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2answers
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Should I be using a composite key for this table?

My database is going to store words, so the Word table is the most important. The Rhyme table lists which words a particular word perfectly rhymes with. It consists of three fields: RhymeID - primary ...
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4answers
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Is this database design sound and fully normalised?

I'm creating a database to store words. The intended usage is to query the database to find a word matching a set of filters. E.g. if I wanted to find a word with < 10 letters, < 3 syllables, ...
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1answer
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When deciding a Primary Key, can I use Date part of a DateTime field

I'm designing a payroll system I have designed a database with several tables and this question is related to following tables EMPLOYEE (Employee_ID [pk], Name,... etc) LOCATION (Location_ID [pk], ...
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2answers
247 views

Should all foreign table references use foreign key constraints

Closely related to: https://softwareengineering.stackexchange.com/q/45447/48651 I asked a question on SO and it led me to ask this here. If I'm faced with a choice of having a circular reference or ...
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1answer
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Is NoSQL a better choice when working with OOP? [closed]

This might be a silly question, but I've reading a little bit about NoSQL databases on the past few days and I'm trying to understand when really they help us. One thing I've realized though is that ...
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0answers
663 views

Redmine - Database Structure/Normalization

I am using redmine for project management and issue tracking. I was looking at the database tables and the underlying structure and was wondering if anyone who is experienced with database ...
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3answers
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What are the use cases for these relationship types?

Use Case What are the use cases for creating a one-to-one relationship where the parent points to the child compared to a child pointing to the parent? If there is no difference, is one preferred ...
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1answer
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What happens if computer crashes after giving commit command

If we are updating a field in SQL and ALTER the row also. After giving the COMMIT command, the system is crashed. What will happen to the commands given, whether it will UPDATE and ALTER the table ...
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1answer
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Is it substandard if I have multiple tables in my database yet there's no relationship at all? [closed]

I have multiple tables in my database. Some tables have relationship to others and some don't have. My friend told me that it is not advisable to have a table that is not related to others. Is it ...
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1answer
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How to represent one special related record

I have two tables, project and photo. photo has ID,projectID,path : each project has multiple photos. Now one of these photos is the one that has to be displayed. The question is how to represent ...
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2answers
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single table w/ extra columns vs multiple tables which duplicate schema

I am working on a project where at some point, I needed to make a decision on whether or not, in the database, I should have a single table with multiple columns that not every record uses, or ...
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3answers
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Tracking correct order details in commerce database when modifying 'products'

I am implementing an ecommerce database. This is slightly different than most as the 'products' that are for sale are for services provided. For example a user (vendor) of the system may define a ...
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1answer
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Relationships in a Chen ERD

I am working on a Chen ERD to model our organizations merchandise. Our central entity is a Style. We have supplemental entities of Color and Season. I am defining our assortment as the ...
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3answers
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Designing a database with circular references for the-one-of-many case

Consider the following case: there are two models Image and User. Users have associated images and they can pick one of them as their profile image. There are essentially two ways of modeling this: 1)...
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2answers
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How should this relationship be structured in a relational database?

In a recent project I was asked to implement an events system. An Event had to have a Location which was originally specced out as simply a physical location with some optional extra notes. Then the ...
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1answer
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Can relational algebra/calculus proofs be used to test/verify SQL?

Is it feasible or even possible to use relational algebra and/or relational calculus in the form of proofs to test/verify the correctness of SQL statements, functions, and stored procedures? It seems ...
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How should I make searching a relational database more efficient? [duplicate]

This is in the scope of a web application. I have a database which has a few nested relations. There is a feature which depicts the history of a large chain of relations. It is essentially a data ...
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4answers
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I want a trivial example of where MongoDB can scale but a relational database will have trouble [closed]

I'm just learning to use MongoDB, and when discussing with other programmers would like a quick example of why NoSQL can be a good choice compared to a traditional RDBMS - however the scenarios I come ...
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Database model for keeping track of likes/shares/comments on blog posts over time

My goal is to keep track of the popular posts on different blog sites based on social network activity at any given time. The goal is not to simply get the most popular now, but instead find posts ...
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1answer
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At what point does caching become necessary for a web application?

I'm considering the architecture for a web application. It's going to be a single page application that updates itself whenever the user selects different information on several forms that are ...
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1answer
354 views

Storing donor addresses in a relational database

I am building a donor database for a non-profit organization and one issue I'm mulling over is how to store some of the donor data. There are some families for whom we capture the names of both ...
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4answers
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Why many designs ignore normalization in RDBMS?

I got to see many designs that normalization wasn't the first consideration in decision making phase. In many cases those designs included more than 30 columns, and the main approach was "to put ...
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1answer
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How can I find all connections in a mesh network/graph?

Suppose I have a mesh of relationships, such as Friends who trust some friends and not others A IPv6 router that needs to locate peers across the Internet A PGP Web Of Trust that needs two people ...
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5answers
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Using Autoincrement Primary keys as Foreign Keys

When creating a table, there is an option for us to set the numeric primary key as autoincrement where its value increases whenever a new data in inserted. This primary number can be used for ...
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5answers
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Planning relational database - one or two tables?

I'm currently planning the database structure of a used car's advertisements site. Each advert contains information about a vehicle, and a vehicle can be advertised multiple times over its lifespan (...
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1answer
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How is data integrity maintained in a clustered environment when schema changes?

Scenario A clustered environment running N identical application nodes interacting with a single relational database. Problem Is it possible to upgrade the nodes to a new application version, which ...
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1answer
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Data integrity in NoSQL situations

Background To start off, at work I work with a legacy system that, in its day, was quite spectacular, but now is ...interesting... to work with. It uses IBM (now Rocket) UniVerse as its backing ...
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7answers
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Should a surrogate key ever be exposed to a user?

Often in a table that has no natural key, it is still useful for users to be able to have a uniquely generated identifier. If the table has a surrogate primary key (and in such a case you would ...
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4answers
865 views

Do these specific tables need surrogate keys?

Background I have this tables +-------------------------+ +------------------------+ |Airport | |Country | |-------------------------| |------------------------| |...
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7answers
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Is there value denoting a key as “Primary”?

Question: Is there value in denoting a key as "Primary"? This question is not about the definition of a primary key. It is not about the fact primary's aren't nullable. It is not about ...
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2answers
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External id for every relational table

Should I add an external id for every table? For example if I have these tables : Customer ======================================= Id Name Gender --------------------------------------- ...
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1answer
745 views

Suitable algorithm for joining records from multiple databases

I am in the process of writing a library that is used to be able to access data from a database. The library requires the initial definition of all the tables that the application will be using in the ...
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2answers
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Handling subscriptions, balances and pricing plan changes [closed]

Preamble My aim is to create reusable code for multiple projects (and also publish it on github) to manage subscriptions. I know about stripe and recurring billing providers, but that's not what this ...
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4answers
352 views

Create a database for database tables

I'm working on a project where I have to give users the ability to build their own tables, each user can create more than one table. (the type of all data is string). The user can create a table and ...
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6answers
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In plain English, what is a database index most similar to? [duplicate]

Setup: Suppose you are teaching an introduction to Databases class, the students are CS students that have a working knowledge of tree structures, how they can speed up searches, and have probably ...
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3answers
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Should lookup tables enumerating strings have an integer primary key?

When I learned relational databases, the prof said that one would "almost always" want an artificial int as the primary key in a table, but did not specify what the exceptions are. At some time I ...
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1answer
347 views

What is the common approach to component template databases?

My Project: I have employees who are required to go through a checklist when they encounter a duck, a cat, and a human. In our business, we have a set number of ducks, cats, and humans that come in ...
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1answer
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Retrieving hierarchy of tree-nodes stored in relational database

I have a hierarchical ADT that I want to store in a database. Nodes have exactly one parent element that is a node as well. Multiple nodes can have the same parent node. My current approach uses an ...
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2answers
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Referential integrity in a database where tuples are not physically deleted

Many modern Relational Database Management Systems automatically support referential integrity, i.e. when you try to delete a tuple which has a reference (in the form of foreign key, for example), the ...
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4answers
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How should I represent an enumerated type in a relational database?

I am working on developing a relational database that tracks transactions that occur on a device I'm working on for my company. There are different types of transactions that could occur on the device,...
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2answers
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Should database-models (conceptual or physical) be reviewed by DBAs?

Where I work, new applications that are being developed that will use their own relational database, must have their database-models (conceptual, then physical ) reviewed and aproved by DBAs. Things ...
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1answer
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Designing persistence schema for BigTable on AppEngine

I have tried to design the datastore schema for a very small application. That schema would have been very simple, if not trivial, using a relational database with foreign keys, many-to-many relations,...
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5answers
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Type of AI to tackle this problem?

I posted this on stackoverflow but want to get your recommendations as well as a user on overflow recommended I post it here. I'm going to say from the beginning that I am not a programmer, I have a ...
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3answers
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On merging database records, constraint violation in the intermediate table of M2M

If you are merging two or more database records from table X, that have a many-to-many relationship with table Y, how should you solve the problem of records in intermediate table Z that would violate ...
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Predicting advantages of database denormalization

I was always taught to strive for the highest Normal Form of database normalization, and we were taught Bernstein's Synthesis algorithm to achieve 3NF. This is all very well and it feels nice to ...
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Should I create an Enum mapping to my database table

I have a database table containing a list of systems relevant to the tool I am building, mostly in-house applications, or third-party systems we receive data from. This table is added to infrequently, ...