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1
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1answer
37 views

Can relational database tables always be topologically sorted by their FK reference relation?

Suppose I have some conceptual, not physical, E-R diagram describing a relational database. I want to sort all the tables in the database using a topological sort, where the partial ordering between ...
8
votes
4answers
3k views

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 ...
3
votes
3answers
74 views

How does Polyglot Persistence handle relational data?

I have recently been studying up on microservices, and an associated idea that I've seen is that of polyglot persistence and microservices working with their own databases, or whatever storage they ...
1
vote
1answer
92 views

Am I planning my database/backend correctly?

I'm an iOS developer and to be honest I'm not really looking to become a database expert right at this moment, but I do need to know how to properly plan out what I believe to be a pretty cookie ...
10
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6answers
1k views

Why is SQL known as a relation-based / functional language?

We're learning that most languages are classified as either of the two, "relation based" or "high level". I've never used SQL before, but from reading its syntax it seems more like the ...
0
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2answers
113 views

Getting to know my way around a database with hundreds of tables [duplicate]

I'm new to a small company that's pretty much run by one guy. He knows all the ins and outs of the system which is quite large. We have a database with about 300 different tables. I'm struggling to ...
0
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1answer
75 views

Reproducing a bug in production that happens with a large database

We are running Oracle 12c and a custom application written in Java/JDBC (Java 8). Our production system is running a 5TB database and runs into deadlocks. However we have been unable to reproduce this ...
0
votes
1answer
51 views

Is there an established pattern for associating a database entry with a Java class that executes on that data?

I have a behavior tree with different leaf nodes that execute tasks. When building out the tree relationship in the database I need an association between the leaf node entry and the Java class that ...
7
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3answers
1k views

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 ...
2
votes
0answers
105 views

Is this a good implementation of mongodb for a money management tool?

I have a money management tool which has users. Each user may have several accounts/funds (e.g. bank account). For each account/fund there may be thousands of transactions. Users may only view their ...
1
vote
1answer
48 views

Looking for advice for the following MS SQL Schema

We currently have the following SQL Schema: Projects Budgets BudgetTabs BudgetSections BudgetTasks BudgetTaskDetails ...
0
votes
3answers
123 views

What is the hierarchical DB schema for this xml?

As per this link, this is the xml that maintains "BookStore" data. I see that number of occurences of author are varying for any book. xml's hierarchical representation of BookStore looks more ...
7
votes
3answers
203 views

How to model and store an entity which has “one or more” values

I'll use C# to design the model to be persisted Let's suppose I have the following entity: public class Episode { public int Id { get; set; } public string Title { get; set; } public ...
4
votes
2answers
118 views

Using audit trail as time machine?

I would like to do SELECT * TABLE t (using data from 1st of march 2012) I already have a nice audit trail of all tables in the database. It basically makes a copy of all rows that change, storing ...
2
votes
1answer
97 views

In a Table Data Gateway, where do I put queries that use joins

The book Pattern of Enterprise Application Architecture has the following description over the Table Data Gateway pattern: “A Table Data Gateway holds all the SQL for accessing a single table or ...
0
votes
0answers
30 views

I have two applications… use NoSQL or RDBMS? [duplicate]

I have two applications in the making: one is a budget management tool; the other is a article based places/restaurant guide. The budget management tool works where users create accounts (e.g. bank ...
4
votes
3answers
135 views

How to track temporal changes in a database?

Imagine a software for theater owners. You can accept reservations for the different cinema halls. Each hall has a different number of seats. Say the owner wants to know how many people visited the ...
2
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2answers
134 views

Alternative locking strategies

I'm having a problem with the design of my application, that neither optimistic nor pessimistic locking tends to solve. Here is a simplified/altered version of the problem that describes the ...
2
votes
2answers
185 views

Should I use relational or noSQL databases for this problem

I'm working on a project where one part is to save data of different people. A typical person might have the following structure: Email: Multiple values possible City: Multiple values possible ...
2
votes
1answer
179 views

How to represent an optional-to-optional relationship in a database

I have two types of users: a CRM user and a system user. We have a record of every CRM user, thanks to a nightly sync that we run (so we don't have to hit the CRM API every time). We have system users ...
0
votes
1answer
201 views

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 ...
5
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2answers
261 views

Database Normalisation - stuck with “categories”

Context: I'm working on a database of museums and Categories will be one way the user will be able to search. e.g click on "Music" and a list of music related museums turn up. Pretty simple. ...
0
votes
1answer
54 views

is there anything called logical schema and the conceptual schema of a database table?

i want to know whether there is anything called logical schema and the conceptual schema of database table. if so what is it.i searched lot of places for this specific two words, but did not find ...
0
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1answer
58 views

Does this Relational Database Model make sense?

Here is a flat version of my datamodel. It is sensor readings for various data acquisition equipment. ...
0
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2answers
257 views

Optimal Database design for 3-way relationship

All right, I know this sounds complicated, but all relationships are, lemme clarify. Well, I have three entities in my database which are tied to each other in a string of relationships, the app is ...
1
vote
5answers
206 views

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 ...
0
votes
0answers
87 views

Fixing data duplication in two similar tables in different databases

I'm currently doing maintenance on an old order system that has grown into the poster child for bad coding practice. One of the tings I'm dealing with is a lot of data duplication, which I want to ...
0
votes
1answer
185 views

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 ...
1
vote
4answers
195 views

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 ...
3
votes
2answers
2k views

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 ...
2
votes
1answer
284 views

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 ...
0
votes
2answers
131 views

Should all foreign table references use foreign key constraints

Closely related to: Foreign key restrictions -> yes or no? 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 just not enforcing ...
2
votes
2answers
108 views

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 ...
3
votes
4answers
756 views

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, ...
2
votes
1answer
813 views

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], ...
0
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4answers
2k views

Is there really Object-relational impedance mismatch?

It is always stated that it is hard to store applications objects in relational databases - the object-relational impedance mismatch - and that is why Document databases are better. However, is there ...
0
votes
1answer
231 views

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 ...
2
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0answers
155 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 ...
1
vote
3answers
70 views

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 ...
0
votes
1answer
298 views

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 ...
2
votes
1answer
125 views

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 ...
1
vote
1answer
44 views

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 ...
3
votes
2answers
3k views

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 ...
2
votes
3answers
361 views

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 ...
2
votes
3answers
491 views

db design: circular references for the-one-of-many case

There are many questions about circular references around (if they are bad or not) but this one will be concrete. Consider the following case. There are two models Image and User. Users have ...
2
votes
2answers
110 views

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 ...
8
votes
1answer
272 views

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 ...
2
votes
2answers
452 views

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 ...
18
votes
4answers
2k views

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 ...
3
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1answer
218 views

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 ...