For questions about structuring the data within a database. How to lay out tables, whether to use a relational DB or not, etc.

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1answer
36 views

Database Object That Reads From Two Tables and Writes to One

I am updating a database design that must be compatible with old and new applications. My goal is to make a design change which minimizes impact on the existing code. The Design Change Currently our ...
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1answer
56 views

Best approach to store huge amount of denormalized/dynamic data with relational database

Here I have a very basic ILS (Integrated Library System) done a long time ago (made with C#/SQL Server), in production for years. But now I have a demand of make this system MARC 21 standard ...
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2answers
52 views

Conditionally show questions based on previous answers in a database driven survey

I'm trying to design survey-type application that uses user responses to determine what the next question should be. For simplicity's sake, question types can be either combo boxes (they have a set ...
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2answers
28 views

Creating a web application with full text search on dynamic data

Even after thorough requirements engineering we end up with users wanting to attach 'notes' to their otherwise well-structured data records, in other words: arbitrary key-value pairs. Their primary ...
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1answer
43 views

The best approach to make a report based in dynamic data

I have an Asp.Net MVC application where I need to create a report. This report will show some data about an entity (activities), but only activities of ONE specific type that will be inserted in the ...
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0answers
69 views

Logging Database Changes

What is the proper way of storing a changelog, similar to git, for data in a database. Currently, I have it set up so that every line in a table is given a unique string id that is used to ...
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0answers
46 views

Saving tabular, spreadsheet-like data in a relational database?

I'm hoping this question isn't too broad or too prone to opinionated answers, since I could really use some pointers. I'm trying to come up with a way to persist tabular, spreadsheet-like1, data in a ...
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2answers
93 views

Database design, processor vs inconsistency

I was wondering, if I have a table that stores, lets say, a user's transactions, then when I need to fetch the user's current balance I would have to go and use SUM() like SELECT SUM(value) FROM ...
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2answers
38 views

How should I structure a DB schema to include multiple market segmentation data?

A client has recently expressed a wish to assign their market segmentation labels to their customers, so that they can sort by market segmentation in their dashboards ("show me all the VIP customers ...
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1answer
53 views

How to associate similar data with different tables in a database?

My application has users and ads. A user has a unique email. An ad belongs to a user (so, the ads table has a user_id FK, that is simple). Every ad can also have multiple emails and phone numbers ...
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1answer
46 views

How to model the database tables for calculating on peak and off peak usage data

I am using MS Sql Server and my system contains power usage data in one table as timestamp and values for KW(two columns). This data is collected at 1 hour interval. At the end of the month I need to ...
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3answers
313 views

How to share a code base among 10+ projects and minimize pain?

I have a number of applications that share the same data in the same database. To try and minimize redundancy of code the Data Access Layer is a shared project. This prevents each project from needing ...
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6answers
180 views

Should I add a “boolean meaning” to another column?

Is it a good/bad practice to add a "boolean meaning" to other fields? For instance, let's say I'm modeling events, that might be recurring or not. I can have: A boolean column that holds if the ...
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1answer
84 views

Getting posts from users that are being followed: two different implementations

I have two different implementations for retrieving posts from the users someone is following and I want to know which one you would recommend using. First I'l show you the tables, and then the two ...
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1answer
70 views

Entity Framework Code First, C# class separation and EAV

I'm in the process of redesigning a portion of my ASP.NET MVC application. I'm currently using Entity Framework 6.1 code first approach. I've been reading as of late that (Correct me if I'm wrong, I ...
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3answers
82 views

Are crow feet notation and uml notation same?

Does crow feet lies under the sub category of the UML notation or it is a whole other approaches. As far i have seen only difference between two of them is that crow feet uses crow symbol ...
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5answers
128 views

Database design - When should a table column actually be a table?

Compare Database #1 and Database #2 below DATABASE #1 POSTS--------------------------------- |___Id________Category_Id______Body__| | 1 "For Sale" "...." | | 2 ...
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2answers
119 views

Proper design for models

I have a class called ReplaceRule this is used by 2 classes DocumentRuleViewModel and SectionRuleViewModel as a List<ReplaceRule> in both Question 1: In my database implementation I have 2 ...
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3answers
47 views

Archiving data by semester

The problem is similar to this question, but not a duplicate. What I'm looking for is a better solution than my current one. I'm building a web application for a department in my university, and due ...
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1answer
62 views

My web app uses a number of photo hosting APIs. What would be an effective database design to store their limitations?

For the sake of an example, let's say I'm using Picasa, Flickr and 500px APIs, and that each of the services has limitations on these simplified parameters: overall account space individual file ...
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1answer
42 views

Full data history, current values can be rebuilt ignoring provisional or invalidated changes

I would like to create a website for a local school and then offer it to others. The school's main headache at the moment is capturing student marks and comments at the end of each school term. The ...
5
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3answers
389 views

Is it ok to have a class that only has boolean properties?

Scenario We have a class Vehicle, this class contains some properties to define the object such as a CarBrand, TransmissionType, Color, etc.. A car (vehicle) also has options, these days a lot of ...
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0answers
33 views

Creating a new table referencing older one vs just creating a column

I'me developing an iOS chat application and working on the db design for the contacts feature. There are 2 kinds of contacts- Unsaved Contacts - Contacts with who you've conversed with, but not ...
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0answers
25 views

Offsetting high usage in a multi-tenant database environment?

I'm writing a research essay over distributed cloud-based systems, and one of the topics that I'm trying to touch on is potential solutions to high database utilization in a single-database ...
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3answers
166 views

When dealing with tens of billions of rows in a web app table, would a NoSQL database be noticeably faster than a relational one? [closed]

I'm currently designing a conceptual web app, where users can submit posts, comments, and "like"/"dislike" both of those. However, I am not sure of how to store the (dis)likes, because of how many ...
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0answers
19 views

Is having a singleton collection in Mongo (i.e. equivalent of an SQL table with one row) an anti-pattern?

I've been looking for ways to implement this, and haven't found it anywhere, so wonder if I'm doing something silly. Essentially I have a set of information which is relevant to the entire ...
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0answers
27 views

Should I use weak entity instead of regular to describe my kind of components?

First time trying to make a E/R model of my database. Trying to understand weak entities and regular entities. Should I make the CPU, RAM, Mainboard, etc. entities weak instead of regular?
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3answers
61 views

What are the theory behind implementing two mirrored HashMaps that can accept write operations? Do I need a broker to mediate conflicting writes?

So imagine two HashMaps that need to be mirrored across two different machines, A and B. Whenever I make a modification to machine A, machine B sees it and vice-versa. Problem is: These two hash maps ...
4
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2answers
61 views

Is it a good idea not to embed certain one-to-one relationships in a Mongo database?

I'm designing a NoSQL database schema - MongoDB in particular - and I'm wondering if it's a good idea not to embed certain one-to-one relationships. For one example, I have an accounts collection, ...
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1answer
61 views

How many vertices/nodes are too many in a graph and stop being beneficial?

Background I'm working on a project that requires me to keep track of transactions as well as the flow of items in a game. In order to do that, I'm storing those transaction in a graph db ...
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3answers
180 views

Use of booleans in a database

I'm using Visual Studio 2013, .Net 4.5 and SQL Management Studio 2012. I have a table that tracks offices in my database. On the application side there are a some display rules regarding the layout ...
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0answers
37 views

Which is the best way to manage multI-account multi-user web application ?

I Am junior web developer, currently I developing school application with PHP and MYSQL, after finishing the app I would like to distribute more schools by allowing them to register in the app and use ...
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5answers
213 views

Is it a bad practice to have a “record status” column in a database table?

I have to clarify first that the status column is not intended to reflect the status of a real-world item represented by the record (row) in the table. Rather, it is intended to show the status of the ...
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1answer
70 views

How to uncouple and reuse persistence logic, user interface logic and business logic amongs embedded software projects

I have been working in embedded devices business more than 5 years as a software engineer. Most of the times our hardware manufacturers provide a Software Development Kit for their reference boards. ...
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2answers
45 views

SQL - Design concepts - Relationships - Referential Integrity - Cascading

THE SCENARIO I learned about basic database design concepts such as basic CRUD operations, referential integrity, relationships, etc., years ago. I've messed around with databases and used this ...
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2answers
58 views

Database error prevention

Im designing a database structure and I would like that it's design could prevent erroneous connections. I'll make a simple example, that I think it will be easy to understand, bellow are the tables: ...
2
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1answer
132 views

How to handle db authentication in multi tenant application with separate databases?

In a multi tenant application with separated databases for each tenant, what would be the best way to authenticate connection to each of these separate databases. My goal is to: Main security ...
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1answer
39 views

Recursive partitioning example

I am trying to understand an example in Chapter 12 (Query Processing) of Database System Concepts, Sixth Edition. A relation does not need recursive partitioning if M > nh +1, or equivalently M ...
2
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1answer
125 views

Should I store cryptographic hashes as a blob or as a string?

I'm new to MongoDB and am wondering how to decide to store some cryptographic hashes. Should I store the binary data itself, as a blob, or should I store its string representation as a string? My ...
2
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1answer
42 views

How to store 1:n self reference (dependencies) in relational database

What is a clean way to store items that reference multiple other items of the same type in a relational database? Say I have a list of jar files and their dependencies: package1 depends on ...
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3answers
112 views

Storing hours a merchant is open in postgres

In postgres, I need to store the hours a merchant is open each week. Essentially, the information you'd see posted on a sign in the merchant's door: Mondays: Closed Tuesday-Friday: 9am-1pm, 2pm-6pm ...
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0answers
32 views

Unifying database interface for multiple authentication methods

I'm working on a project with Mongo as the db. Currently, we only allow users to sign up with email and we look them up in the db by email address. But now we're moving to allow users to sign up ...
2
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0answers
145 views

How should I store usernames and passwords for user login using php/cassandra?

I am new to NOSQL and Cassandra. I am not sure if I should store usernames and password in Cassandra. If I should, what is the best way to do that? I am getting lots of conflicting ideas from ...
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2answers
56 views

DB Design for non static front-end

I have a question about best practices to design a database which have to hold the following data: There is a page with a questionnaire which has default questions like Firstname, Lastname, Street... ...
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0answers
27 views

Best way to create “attributes” for Neo4j node?

I have this node labeled "Person" and these various items from what would be a class, in a conventional DB. For example: Teacher, Lumber, Magician, Artist and Painter. They should all fit in the same ...
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1answer
43 views

User account model with two or three possible profile

My application will have at least two types of users: clients and companies, these are the types of profiles. Because each type of profile requires different additional information, it will be ...
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2answers
63 views

Difficult design with multiple associations between two entities

I'm trying to design the data schema and the restful api for a specific case. In my system I have several users and several books. Every book can have several users as authors and at the same time ...
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3answers
150 views

How can I store incomplete records but enforce data correctness?

I'm in the planning/design stages of a new project, and I'm having trouble coming up with a good way to handle one of the requirements: Users must be able to create a new record and save it as ...
2
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2answers
112 views

Database Design - lots of small tables or fewer, bigger tables?

So I'm designing a database for a project which is going to enable beauty businesses to create a profile, clients to create a profile and for the client's to be able to book appointments and for the ...
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2answers
82 views

Junction table related to another junction table

I'm defining a DB structure, and I have a strong feeling I'm not doing it right. I have hotels that can be configured to offer some optional services (airport pickup, massage), that can in turn be ...