The logical model and/or physical design of a database.

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1answer
52 views

Split data across databases/machines

I have two questions about how to partition data across servers. Can I create and connect two or more databases, with the records correctly associated, using only a mapping table stored in a third (...
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1answer
53 views

Explaining how to design a database to model the stocks of a firm to my Grand'ma

My teacher always asked us to create simple but precise databases. Being able to explain it simply but not without leaving the theory "to your wise but aged loved Grand'ma"... I have to create a ...
2
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1answer
81 views

Minimal 3NF normalization issues

I'm trying to learn how to normalize to 3NF but the example that my teacher gave us doesn't really help. The algorithm I always used is this one: Find a canonical cover F_c for F For each FD X->Y ...
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2answers
45 views

Design problem with placing proper constrains

I have been trying to solve this problem but in every solution there seems to be something missing. So we have organization for collecting donations from donors for people that need help. Member can ...
1
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1answer
29 views

finding out the metadata and joins

Suppose I have a database with a large number of tables. Is there any command that I can type in PL/SQL which display only the field names of a given table? Given any table is there any command ...
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1answer
48 views

relation between customer and product with review

I draw this ERD but I'm not sure if the relation in customer and product with review is correct. also, is it right that I made Rate, Date and time this way ? this is my Description for review Each ...
3
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2answers
115 views

Table with only a single constant value?

I use C# entity framework code first. My knowledge regarding databases is almost nothing. I don't know if it's common or good practice so I wanted to ask you guys how I should do it. Say I have a ...
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1answer
39 views

Creating an exam center database

I am making an app than has an exam center... I am aware of the database normalization concepts...but in my case it looks like I need to store non atomic values in a column. Actually the app will have ...
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1answer
63 views

Database design for a lot of rows with data archive

i'm new to database design on larger scale. I have some knowledge and experience with MySQL but now i have some performance issues. Currently i'm using MySQL with 3 databases: History Snapshot ...
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1answer
58 views

Searching from Database having billion records, which database should i use [duplicate]

We are having 1 billion phone numbers and we have to search them against numbers which we send for promotion to filter out which are not promotional registered. That is we have lets say 1 million ...
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1answer
46 views

Relationships mess

Say I have a table ads, and each ad has several medias - held in a medias table. Each media can be one of several types. Types are in a media_types table. So, for example, an ad has two medias: one ...
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1answer
22 views

Database Schema for a User and his variable number of items

I planning to create tables which hold data related to my users. These tables contain the items that each user owns, and there is no exhaustive list of all the item. The number of items owned by a ...
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2answers
42 views

Good learning source for learning normalization [closed]

Can anyone recommend a good learning source to learn about database normalization from scratch please? I referred to many youtube videos but they weren't fit to me.
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0answers
29 views

Database schema design for dynamic CRM with inter-account interaction

In a traditional CRM, we have some basic objects such as users, organisations and contacts. The users belong to an organisation's CRM account. A very basic schema might look like this: User ---- id ...
3
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0answers
46 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 ...
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3answers
120 views

Mysql - How number of columns effect the database performance

I have a table to store social media information for users; I have 42 columns to store and will have 100000 entries per day to store. I am planning to have MyIsam engine for it and will use horizontal ...
0
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0answers
15 views

What is a fast way to calculate counts and sums?

I have the following data: A journey which contains this info: - a geohash (to identify the location) - a journey_id - whether this was the start or end of the journey - the cost of the journey I ...
1
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1answer
25 views

Does the existence of a college course depend on the department in which it is studied?

I have a Department entity along with a Course entity, does the course entity depend on the department or is it a strong entity by itself since it has an ID that can distinguish it from other entities?...
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0answers
29 views

Does an exam entity in a student information system depend on the department or the student?

I have made an ER Diagram for a student information system where I have the following entities: Student Department Course Administrator Exam Attendance I'm having trouble determining whether Exam ...
0
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1answer
34 views

Which isolation level do I need?

I've read a lot of articles about Isolation levels, but I'm confused which one to choose for my MySQL 5.6 database. This is my situation: Let's say I have two group of users: Group A (...
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0answers
40 views

Registration Schema Implementation

I'm building an online app that is going to handle reservations. Individuals making reservations can make one for a single day or multiple days. I have come up with two schema and cannot see much of a ...
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0answers
23 views

Address database scheme - multiple links

I am currently building a databse scheme for a small company. But at the point doing it I figured out that my attept will be unacceptable due to the ability that one action will affect multiple ...
3
votes
2answers
86 views

One-to-many to multiple tables

What's the normal way to design a relationship where every entry in table A is connected(1:n) to either an entry in table B or table C? Or specifically: There are a tables for characters, movies, ...
0
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1answer
51 views

How to store Alternate Names for Places or City in Table

What is best way to store Alternate Names of the Places (City or Locality) in MySQL database columns which user will be searching? Examples: In India user may search for "Chennai" or "Madras" and ...
2
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0answers
40 views

insert/update from web server or database

I have a data-model on the front-end that I want to insert/update in the database which of the following approaches (or neither!) is considered best practice: # in webserver some_model = {json} ...
3
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1answer
75 views

Database design decision help

I currently have a database design that I have been looking at and I am wondering if its the best one. I have the following tables: Each request has a current status. I need to keep track of all ...
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0answers
23 views

Database design for efficient read queries given lots of writes

I have a PostgreSQL database, and an application which receives around 200 requests per second. Each of those requests contains a message with an identifier representing a journey id, a timestamp, ...
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1answer
123 views

How to efficiently design MongoDB database for Uber-like application?

I'm designing a MongoDB database for an Uber-like application, but since I'm new to NoSQL concept, I have several doubts. I have three main collections - users, requests and messages. User can post a ...
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0answers
77 views

How could I improve speed of fetch in Oracle?

I've got a table of taxi GPS trajectory records with approx 60 million rows, including date, time, ID, longitude, latitude, speed, bearing etc., which were imported from .csv files with setting each ...
3
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1answer
70 views

which way is better to design shopping Cart Table - SQL Server

I want to create a shopping cart in an online store. I have two ways to design shopping cart, but I don't know which one is better. Solution 1: create a table like below : in this way for each ...
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0answers
30 views

How to store general information about an entity

I am designing a database to store data relating to management of a school. I have tables representing the sorts of things you would imagine: Students Carers Invoices and so on. One feature I wish ...
2
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1answer
77 views

Is it bad practice to use separate columns for parts of date values?

I recently posted these questions in order to try and improve the performance for my queries. DBA Q&A 1 DBA Q&A 2 One of the suggestions was that I should use a DATE() column rather than ...
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8answers
2k views

What problems are solved by splitting street addresses into individual columns?

We have a team who designs the tables and relations for software developers. In our organization, they are pretty strict about enforcing 3NF normalization - which to be honest, I agree with given the ...
3
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0answers
50 views

Ranking items on a per user basis

I have a MySQL DB with 20k-50k items and I want various users (let's say 1k-10k) to rank these items for themselves, so this is not going to be a global ranking but a per user one. All items are ...
3
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2answers
84 views

Database model about libraries

I need to make database model about libraries. In that model I'm tracking more libraries and every library has it's own moderators. Every moderator can make categories of the books and than add books ...
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1answer
28 views

Best way to apply a “friend system”-like table? [duplicate]

I am making a website that has multiplayer games like chess, poker, etc. Users will be able to add friends. I was thinking about how could I make this in a DB, and I thought of two methods: 1 - ...
5
votes
2answers
176 views

Is it possible for a weak entity, already related to a strong entity, to get related to another weak entity in an ER diagram?

I have a problem statement (briefed), Database for a Fitness Club - Client's Attributes: Name, Address, Ph. No. Membership Plan's Attributes: Beg. date, Sub. Fee, Monthly Fee, Duration ...
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1answer
28 views

Is row based or column based raw input better?

I have a vendor that is starting to give me some rather large reports on course completions and usage. They have two formats for the reports: If a student is enrolled in a course, they will have an ...
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1answer
86 views

how can I add multiple values in a single column?

I'm working on a project and I have a scenario We have a vendors table, some vendors have many contact no. how can i add multiple phone numbers on a single contact no. column?
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0answers
21 views

Efficient Provision of Multiple Versions of Data

We have a fairly unusual database use case: we have a number of large datasets used for research (the largest being a couple of billion rows). The datasets are used by potentially several hundred ...
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2answers
45 views

One connection vs multi connection

I'm redesigning my client's website in order to add about 16 mini sites for their web site. It's a website using PostgreSQL. And my question is: Performance wise, what is the better database design: ...
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0answers
38 views

Handling Strong and Weak entity types in a one-to-one relationship

I am modelling a database for a term project and I have come across something I do not have a definite answer to. Diagram I was supplied with the following Entity-Relationship diagram: ...
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1answer
48 views

How to store user activity that supports undo?

I can track user activity on posts, so that users can see for example "2 updates!". The essence of the strategy I’m using leverages 2 tables: post_activity: post_id | user_id | time_created ...
3
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0answers
41 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 ...
1
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0answers
25 views

creation of stack exchange as a project [closed]

I have been given a project to create a database for stack exchange. should I use a single database for all the sites or I should create a separate database for each site and link them
0
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1answer
28 views

How to show the Join with Crows Foot Notation

I could be barking up the wrong tree, but I'm trying to illustrate not only what the relationship is between entities, example, Customers shop in many stores, but also how to join the two entities. ...
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1answer
62 views

Database design for ordering complex products

I'm working on a platform in which you can order food from different sellers. Currently the platform is working and restaurants can create food products while clients can order them. Easy enough. A ...
0
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1answer
45 views

Should a TeamMembers table have a relationship with the Student Table or the Enrolment Table?

I'll keep it nice and short and simply link to the ERD: Users can be assigned a role, one of those is student. So for the sake of this, Students are the same as Users! A Student can be enrolled in ...
0
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1answer
35 views

Question regarding database design

I want to store data of customers and employees. What I am having trouble deciding is what is the correct thing to do: a. Option a: Two tables - Customer and Employee b. Option b: Three tables - ...
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27 views

Microsoft Access Form's Combo Boxes Help

I have a database in access and I am creating a form to enter transactions for investors in our hedge fund. The form is supposed to create new records in the table tblTransactionsAccrued. I created a ...