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Questions tagged [database-design]

The development of the conceptual schema and/or the logical model and/or the physical settings of a database.

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10k views

Conceptual data model for a billing system

I am working on existing MySQL database. My task is to create a new data model for a billing system on that existing application. I have created a conceptual data model (click to enlarge): ...
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0answers
990 views

Working on a decision tree database design

I'm doing the conceptual model for a Decision tree database. The goal is store any Decision tree. I have four entity types: DecisionTree, Node, Branch and Leaf. Each Decision tree is composed of ...
5
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0answers
81 views

Which data model/schema to apply to a timeseries datastore for data sources with varying fields

I'm asked to develop a data-storage for time-series data, yet despite significant research I'm unsure about the data model and storage technology to chose. About the data The source data which is ...
4
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0answers
104 views

Database design for ~ 2.7B rows per year / 26.000 data points every five minutes

The current situation We're currently looking into a new product that will send device data back to us to interpret. These are the numbers we're looking at: Devices will most likely send data every ...
4
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0answers
72 views

Can the Chase test algorithm only modify attributes on the right side of a functional dependency?

I'm attempting to apply the Chase Algorithm to determine if a decomposition is a lossless join decomposition. Functional Dependencies = {A → C, B → D, C → D, DE → C, CE → A} Here is my initial ...
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0answers
687 views

Personal Finance database review

G'Day, I found that someone had started on this topic on personal finance, I like to go further using a good personal finance plan I found on the internet which I would model. In advance please ...
4
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0answers
925 views

How to properly configure pgBouncer transaction level pooling?

What is a good way to determine the number of available transaction connections when using pgBouncer to pool database connections? Also, how should I determine the number of max_connections and ...
4
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0answers
973 views

Dynamic MySQL partitioning based on Unix Time

My DB design includes multiple MYISAM tables with measurements collected online, Each row record contains auto-incremented id, some data and an integer representing Unix time. I am designing an ...
3
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0answers
39 views

Versioning rows in a table

So I have this concept in my head of "immutable" records, which I am sure is not novel, but can't seem to find the right google keywords. Basically, historical row values need to be preserved as '...
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0answers
59 views

Third Normal Form (3NF) Decomposition Scenario

I am trying to understand what are the steps to check if a decomposition of table is in 3NF. There is a specific exercise I'm trying to solve with no success. Given that R={A1,A2,A3,A4} and F={A1→...
3
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0answers
58 views

How to efficiently store 672 bits of information in PostgreSQL

I have a requirement that needs to store lots of bits and it's actually a time setting for every 15 minutes in a week (indicating if a user is free during that time). So for one day we need: 60 ...
3
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0answers
27 views

How to design a database for my entity-relationship diagram about Projects, Tasks and Developers

I'm new to database and my entity-relationship diagram is as follows: According to that I designed my SQL-DDL database statements as shown below: CREATE TABLE Developer ( DeveloperID int NOT ...
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0answers
62 views

How to design normalized relations to store “global/generic” data?

Context I was designing a relational database model to store data about a company and its production facilities. I had a facility relation and many other relations referencing it, most of the time ...
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0answers
81 views

Modeling a database structure for a trip management business domain

I am sketching up a database design and it is giving me some troubles. Basically something just "smells" about this design but I can't seem to arrive at a better way to do it. For example, the Joins ...
3
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0answers
2k views

How do you perform the chase test?

Trying to follow the chase algorithm as I understand it, If two rows agree in the left side of a functional dependency (FD for brevity), make their right sides agree too. Always replace a ...
3
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0answers
424 views

Which SQL Power Architect type to specify for [PostgreSQL] UUIDs/GUIDs in new column property template/UI?

I have inherited maintaining and extending SQL Power Architect projects in source control which are used to generate the DDL for project DB schemas. We are currently using PostgreSQL 9.5 and SQL Power ...
3
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0answers
72 views

When to Converge Dimensions in a Data Warehouse When There Are Few Common Attributes

I have two StudentDetails dimension tables in my data warehouse and I want to know whether I should converge them, considering that they have limited attributes in common (keeping in mind Kimball DW ...
3
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0answers
676 views

Supertype table with disjoint subtypes in MySQL

I want to have base parent table with few disjoint subtypes. To illustrate what I mean: CREATE TABLE issues ( issue_id SERIAL PRIMARY_KEY, issue_type CHAR(1) CHECK (issue_type IN ('B', 'F')), ...
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0answers
144 views

Conceptual Diagram advice for varying Product and History states

AIM: A MsSQL DB to hold Products / services that will vary significantly, although there won't be many; hence, the N:N attributes for ProductTypes. Be able to keep a record of Product changes [Price, ...
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0answers
346 views

Normalization vs denormalization for these kind of data?

I'm using Firebase realtime database (NoSQL), And trying to figure out the best database design for my data. My data is primarily about discounts, each affiliator introduces a number of discount ...
3
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0answers
548 views

How to model a price discount with a purchase of several products as condition?

Scenario Let us say that, in my business context, there are three different products, i.e., product one, two and three, and I wish to offer price discounts when a condition like the following one ...
3
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0answers
246 views

Is it good practice to have multiple keyspaces in Cassandra?

I've Cassandra configured on Amazon EC2 having 3 nodes(instances) in single cluster. Now what I want to do is give some space on Cassandra to my clients by creating separate keyspace for each in a ...
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0answers
341 views

Anchoring values for a rating or likert scale

I am designing a schema for an interview system as per the suggestion in this answer. I need to store several different types of questions: Questions with a free-text response Multiple choice text-...
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0answers
213 views

Inputting auto-incrementing, grouped, unique hashes?

Alright, here's what I've come up with so far: SET @id=(SELECT IFNULL(MAX(id) + 1, 0) FROM leads); UPDATE leads SET id=@id WHERE id IN ( SELECT id FROM (SELECT * FROM leads) AS something WHERE ...
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0answers
311 views

Database Designs Alternative to Polymorphism in Establishing Relationships

I'm working on a database which handles replacement of parts in a machine. Rules A machine has many components A machine has a set of assembly instructions Many components have many part (screws, ...
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0answers
209 views

Could I use both UUID and Sequential ID or is it bad design

Sequential IDs have pros and cons. UUIDs have pros and cons too. Why not use both for each table? (Let's say I have -and will have- no problem about storage space) I could use: UUID for exposition, ...
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0answers
638 views

ERD for a Contract between a Writer and a Publisher: Is it correct, can it be simpler?

I created an entity-relationship diagram (ERD) for a book publishing business context that I will detail bellow. Entity types The entity types of interest are: Writer Work (as a book) Publisher ...
3
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0answers
364 views

Class-table inheritance without flag column

I am trying to implement proper Class Table Inheritance (aka Table Per Type Inheritance) in mySQL. AFAIK it's not offered out of the box so some hacking around is needed to make it tick. Current ...
3
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0answers
104 views

SQL Server storing predefined value sets along with open values

I have Cars with different Characteristics, Characteristics have values, which can be restricted by predefined set of values or be "open" values (any string). Characteristics and predefined values ...
3
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0answers
98 views

Is this user-storage database system efficient, effective and secure?

I am using: PHP Version 5.2.17-MIT-BACKPORT-GnuTLS SQLite 2.8.17 I have a database called users, which currently has a table called root. There will be others, once I get all the rows for root ...
3
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0answers
118 views

How to relate a “parent common” table with its (possibly many) “subtype” tables?

I am having a bit of a brain freeze. I have a table whose properties are the root of four distinct elements, for example: I need to relate SystemType to a SystemCommon, where one SystemCommon can ...
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0answers
76 views

why some one will use approximate data types for sales

I was messing around with Kartris online shop and I was reading this definition for a product version(you have basic information of a product in one table and many versions of products wich can have ...
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0answers
419 views

transaction replication causing too many deadlocks after adding a indexed view - what to monitor in order to avoid this?

I have created the following indexed view and its clustered index: This view was created on a subscriber database and all the tables used in the view are constantly being written to through the ...
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0answers
84 views

One table or four?

I have four entities: Absence { ID, StartDate, EndDate, Days, Hours, Reason } Overtime { ID, Reason, Date (Integer), Hours (Integer) } Time in lieu { ID, Reason, Date, Hours } Holiday { ID, ...
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0answers
61 views

How do I design a database for different sets of measurements on different subjects?

I'm conducting a research project that consists in sampling different physical quantities on about 30 buildings, most of them single-family houses. Some of those physical quantities will be common to ...
3
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0answers
415 views

Replicating databases for local and cloud instances

Forgive me if this is an inappropriate place for this architectural question but I'm not sure where it best fits in the StackExchange family. I have been tasked with developing an online/live auction ...
3
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0answers
221 views

Database describing databases and references to tables

Context The company I work for makes a number of different softwares each with its own database. As they're all about related things (accounting) a good amount of data is theoretically the same among ...
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0answers
24 views

A multiple choice question, with multiple or only one correct answer, and sometimes no correct answer

It's a question & answer based model, and here is the scenario: A question with multiple choices given, with 3 to 7 correct answers among those choices. A question with multiple choices given, ...
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0answers
58 views

What's the more performant database design for query speed and write overhead when storing many boolean columns?

Setting the scene I have a PostgreSQL 11 database running on a very fast 64core, 10 SSD HW RAID 10 server. In the database I need to create a table with a couple of million rows, let's call it cars. ...
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0answers
31 views

Database Design for tracking user flow

I want to design a user tracking system between different tables/models. I want to track the user's progress. There is a Module table which is related to sections and sections are related to sub-...
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0answers
23 views

How to handle normalizing the concept of a grid, and also plan for data versioning?

I have inherited a database that has a normalized structure, except for its data tables which are aggressively denormalized. Our system mostly renders grids into a browser, and the previous developer ...
2
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0answers
38 views

How To Query Databases in Subject-Predicate Format?

I have csv data in this format: id fieldname fieldvalue -- --------- ---------- 1 fieldA A1 1 fieldB B1 2 fieldA A2 2 fieldA B2 If I upload this to MySQL, how can I ...
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0answers
33 views

Basic company and user registration database - Pulling my hair out

I have now created a partially working database, although I feel I have over complicated things, and also, not sure where to add the extra tables/relationships required. First off all, I have a ...
2
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0answers
63 views

Non-standard number data types in Oracle

I'm not sure that this question belongs to this StackExchange. I've asked this question on StackOverflow: Besides the "usual" number data type where precision is greater then scale there are ...
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0answers
25 views

Is it correct that functional dependencies are not symmetrical?

Say we have a relation R(A, B, C). We have one known functional dependency: A → B. I'm wondering if it's true that there would be no way to prove that A → B implies B → A. If it was true, I can't ...
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0answers
35 views

How costly is changing column datatype in PostgreSQL?

I'm currently evaluating PostgreSQL for an app we are developing which comes with a weird usecase. We want to allow clients to create new fields which in turn will create new columns in a client-...
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0answers
50 views

Is this “idiosyncratic” method to manage constraints declarations beneficial?

I just wanted to get feedback from actual DBAs, based on their experience and knlowledge of database theory, in regards to this. At my company, we have a large .sql file that holds all of our schema ...
2
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0answers
98 views

Modelling a database for a simple IT device tracking scenario

Sorry, my English is not that good. I need a simple IT device tracking sytem at work. For each device I need to know its current location, status and ownership (employee to which it is assigned). ...
2
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0answers
262 views

Database design for Subscription, Coupons and Plans

I have searched a lot in SO and SE but I did not get anything particularly about this kind of database design with coupon codes included. Please take a look at this problem. I am developing a website ...
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0answers
46 views

Needing some guidance on designing a DB

So I am not a coder, clearly. I'm hoping that someone would be kind enough to understand my situation and help me ask the right questions to have a DB designed for my needs. I currently use Excel to ...