Questions tagged [rdbms]
The rdbms tag has no usage guidance.
69 questions
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Constraint to enforce pairwise distinctness of values in two columns in table
I'm kind of stumped by a seemingly simple problem in Db design, but the more I think about about it, the more it twists my mind.
Let's say I have columns C1 and C2 in a table. How do I enforce that ...
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Why is the highest NUMERIC precision in most RDBMS 38?
SQL-92 says:
16)For the <exact numeric type>s DECIMAL and NUMERIC:
a) The maximum value of <precision> is implementation-defined.
<precision> ...
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3
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466
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Avoid race condition using RDBMS transaction
I am working on design of a distributed system which will process some events. For simplicity lets say, multiple instance of same service will be consuming from same queue, every message will have a ...
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187
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How is B-Tree used in DBMS-s if WHERE condition can be anything?
The most of the database management systems use B-tree as a data structure for increasing the performance.
Let's imagine that we have a table users with the following columns: id (int), name (string), ...
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2
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510
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Should I store non-editable items lists in a database?
Relational database is mostly used for storing editable user data.
But how about storing non-editable lists of information? Possible examples are:
GUI-related: main menu items, selectbox options, ...
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790
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Event Sourcing inside a RDBMS
I'm thinking about using an Event Sourcing / Event Store pattern in my RDBMS designs.
What I mean by Event Store is a pattern where each data mutation (INSERT / UPDATE / DELETE) is persisted as an ...
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2
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174
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Do I need to use Apache Kafka alongside another DBMS in my use case?
I have a project that relies on getting data from IoT devices.
then I display the data analytics using a graph (in real-time) and also the state of the machines (are they working or not and the reason ...
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Does it make sense for a large scale SaaS project to use a single all powerful SQL/RDBMS database?
Scalability seems to be a thing now.
I was in a heated argument with one of my developer who insist on using MySQL for a data intensive application we are building. MySql is easy, fits the purpose and ...
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2
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801
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Isn't data migration a major benefit of MongoDB compared to the commonly used relational databases?
I was reading an old answer which was recently updated, and noticed that the author doesn't quote the simplicity of data migration as a benefit of MongoDB. I always thought that the major benefit of a ...
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139
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Combining relational and document database for movies
As a architecture design brainstorm, I am pondering on how should I define schemas for movie database where heavy text searching is delegated to document based database (eg. elasticseach) while rdbms ...
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141
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In DBMS are Secondary Indices ordered?
I've read that the Heap File Organization is usually used to structure a secondary index. This makes me suspect that usually, a secondary index is unordered, as opposed to the primary index, that is ...
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139
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What is a good datastructure for localizable tags? (Like a blog post or questions at SE getting tagged with)
I am developing a web application where users can upload images and add tags to them. Because the audience is very international, I want the app as well as the content to be localizable.
Most of the ...
user334372
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229
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In a parent table - Child table relation , where to store order of children
Assume a Parent -> Child relationship in RDBMS.
questionnaire table and question table.
question table has a foreign key questionnaire_id to store which questionnaire it belongs to.
Questionaire ...
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1
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137
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Combine Ids to a single field
I would like to ask if there is any powerful method we can use to combine the Id's to a single field for faster search and retrieval.
My case is like this, I have a table that stores ID's of ...
- 101
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2
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136
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how to model 2 objects that refer to each other in the DB
Now I have 2 objects which are "PROBLEM" and "SOLUTION", obviously "SOLUTION" is a proposed solution to a given "PROBLEM", my problem is that in my business I have the following relations:
a "...
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14
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Is there any technical reason why, in programming, the default date format is YYYYMMDD and not something else?
Is there any engineering reason why is it like that? I was wondering in the case of a RDBMS that it had something to do with performance, since a "YEAR" is more specific than a "MONTH", for instance: ...
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Application analytics - Logging with NoSQL/RDBMS, BigData [closed]
I need to architect a system for my company. My question is specific to logging. Part of the requirement is to log 2 kinds of data.
A1. User events (Ex: UserA clicked on Button1, performed Action#21. ...
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Should I use NoSQL (MongoDB) or SQL (postgresql) database for my application?
I am planning to build a live audience interaction webapp similar to Slido as practice/fun project.
User groups: admins and anonymous users
Admins:
login
create event (define event period and ...
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2
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732
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Building a scalable Email Delivery system
I want to fix my current Email Delivery system which sends email using a third-party email provider and creates a record for each email sent in RDS. Functionally this is how the system behaves -
A ...
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218
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Optimistic locking vs separate lock store for background workers
I need to compute the value of a row R on a table based on rows queried on another table B.
I need to do it in a queue worker because the computation of the value can be slow. A message is queued ...
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Can traditional SQL databases be fully replaced by NewSQL?
I've recently learnt about "NewSQL" databases like:
Google Cloud Spanner (proprietary)
Microsoft Azure Cosmos DB (proprietary)
CockroachDB (open source)
also see How does CockroachDB compare to ...
- 1,559
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How does client connect to replication server in oracle?
I have read couple of articles on google but not sure how DB client for example java application connect to clustered DB.
All the articles I read says client will write at master node but will use ...
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OLTP vs OLAP - MongoDB
RDBMS design often emphasizes data normalization (especially 3 NF) for the sake of efficient transaction processing (OLTP). OLTP is the predominant use case for an RDBMS.
Goals of Normalization in ...
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Using MongoDB for not scalable application?
I have mainly worked on RDBMS databases. Recently studied MongoDB and liked where we don't have to define schemas upfront. So application developers straightaway can start writing the code. Major ...
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3
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964
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Best Practice regarding table schema
We are discussing in team regarding best practices.
For eg. there are three tables
Users
Groups
Teams
A user will create a request to join a Team or Group or to follow a Private User.
A request ...
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16k
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Should I define the relations between tables in the database or just in code?
In my experience, many of the projects I have read in the past didn't have relationship definitions in the database, instead they only defined them in the source code. So I'm wondering what are the ...
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130
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Might this be a good candidate for a graph database? [closed]
We need to create an application that must diff relationships between entities.
As an example, let's say we're creating an application to model instances of a disease amongst pets, and we ...
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394
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What is a simple way to store data for word count purposes?
I am writing a program to crawl the web and find frequently used words. What would be a good way to store the data? I was thinning of using an RDBMS with a single table (with columns 'word' and 'count'...
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Migrating MYSQL functions and stored procedures to SQL Server
The company i'm working for is selling HRIS management software. It was built using ASP and mysql. But one of our client's demand is for it to be based on MS SQL Server. our team is made up mostly of ...
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Design activities / events logging (ex: fields update) in RDBMS
I am trying to implement a activity tracking system in Ruby on Rails for an API only application.
I have a table named letter with information as follow :
id (primary key)
sender_id (foreign_key on ...
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605
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RDBMS v/s NoSQL for analytics [closed]
While reading about this topic online I have found out that, in general, RDBMS are good for read heavy loads and NoSQL databases are good for write heavy workloads. This statement also seemed true ...
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Why not just make non-parameterized queries return an error?
SQL injection is a very serious security issue, in large part because it's so easy to get it wrong: the obvious, intuitive way to build a query incorporating user input leaves you vulnerable, and the ...
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Do common relational database systems work 'out of the box'? [closed]
I'm quite new to software development and whenever I come across small projects which involve storing (relational) data I always ask myself if something like a micro-blog (or any other project with ...
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Should I use BLOB or Tables for storing large data?
Problem
Currently investigating a solution to improve the performance of a web application. The application works well for small projects, but faces performance issues in the UI when working with ...
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Chat-service database design
I have an android/desktop application that I'm now releasing on the web and, as there are some social aspects, I thought of adding a chat-service so users can IM as well.
For this chat service, I want ...
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user verification value - where to store [closed]
Quick question as relates to database.
Where would you store the value of "UserVerified"? (The one that occurs after the user has checked his email and clicked on the "Verify" link with the hash ...
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RDBMS (MySQL) logic question. How to join multiple "FRIENDS"
so this is a logic question as to creating the proper relationships in a MySQL database.
What logic would you choose for the following scenario?
This is a back-end for an app where people can have ...
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DB modeling for staffing demand and supply
TL;DR - I'm looking for guidance with my database design. I am concerned that my existing design is inefficient and won't be able to handle large numbers of employees.
This is going to be long, so ...
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Best solution for a large database transaction
I have a COBOL CICS process running on a mainframe legacy system. The process does over 2K DMLs in a highly concurrent DB environment. After each CRUD operation, the result is used to make further ...
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Would these two scenarios be good candidates for a NoSQL database?
I've checked a few other threads around the topic and search around, I am wondering if someone can give me a clear direction as to why should I consider NoSQL and which one (since there are quite a ...
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alerting that an object cannot be deleted (due to constraints)
Assume an application with a rich domain model with many classes (e.g School, Classroom, Teacher, Student, Course, Exam, Submission, ...) linking to each other. Model and links are mapped to the ...
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What's the name of this category of variables (NEW, OLD, etc) available inside triggers?
I need to do some very specific web search, but in order to do that I need to know what's the technical name of the category/type of variables like NEW, OLD, USER ( the could be more ) that you can ...
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MongoDB: Replicate data in documents vs. “join”
Disclaimer: This is a question derived from this one.
What do you think about the following example of use case?
I have a table containing orders.
These orders has a lot of related information ...
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543
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Desktop GUI Client - Remote RDBMS communication
Sorry if I am asking a trivial question but I have been searching for a while without any luck. I need to design a system and I am looking for advice on the technology that should be used.
The layout ...
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Lucene + Joins == RDBMS?
Now that Lucene supports joins (at indexing time and at querying time) can one use Lucene as a databse (a NoSQL one, with Eventual Consistency)?
Note: I was pondering on that for sometime and this is ...
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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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Why don't RDBMSes return joined tables in a nested format?
For example, say I want to fetch a User and all of his phone numbers and email addresses. The phone numbers and emails are stored in separate tables, One user to many phones/emails. I can do this ...
- 1,889
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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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In what order are rows fetched absent ORDER BY clause?
One programmer is testing and comparing the same application which uses the same database structure, and the same data, only in two separate databases, one with Oracle 8 and one with Oracle 9.
The ...
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Why should a column in a Relational Database have a single purpose?
Consider a table in which a column represents a monetary value in some cases and a link to the value of another record in other cases so that we have the following:
TABLE 1
Id Product Composite
1 ...
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