Database design is the process of specifying the logical and/or physical parts of a database. The goal of database design is to make a representation of some "universe of discourse" - the types of facts, business rules and other requirements that the database is intended to model.

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MySQL created_by or updated_last-by [closed]

I've been giving the task of taking SQL DDL from data modeler and to transcribe it into mySQL for an internship. The only thing I cannot figure out is how to take Created_By VARCHAR2(30) DEFAULT ...
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23 views

What pivot tables to use for User Event Registration with Events and Sub Events

I need to design a database for an application to register and review attendees for events. But There is a complication I don't know how to deal with The event they can register for is for a month, ...
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50 views

Should I put common fields in each specific tables or one common table then join when data selecting?

Assuming there are a few categories: blog, video, gallery. Each of them contains post data like id, title, content, author, create_at, but different category have few more specific field: video will ...
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33 views

How to design a demographics database?

I have a bunch of stores. Each store has the same properties (ethnicity, marital status, income, and so on). Each of those properties has subproperties like (white, black, asian for ethnicity and ...
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123 views

one table for all blob with a one to one table for metadata which link to one or many tables?

I'm going to start by saying that I'm not a DBA but i got that role in my current project so I'm doing my best. The application must be able to store files(attachments, official documents, etc) The ...
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24 views

Additional info on some rows in the table

I am trying to design an MS Access 2013 database to keep track of an inventory of items. All items have certain common properties, like name, date they were stored, location of the physical item, ...
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2answers
73 views

Is it ok to have 40+ columns in a table

I am currently re-designing some of DB's for a project. There is one DB in particular that is giving me a little of a headache. The idea is that for every client_id and date (client_id + date would be ...
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Professor told us to store serialized Java objects as blobs instead of defining relational tables

Instead of actually defining a tables with the correct attributes, my professor told us we could map objects to ids like this: id (int) | Serialized Object (blob) 1 10010110110 ...
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22 views

reports on history table

Assume Trucks which travel between Cityies. I store the Cityies that a Truck has traveled to in TruckLocationHistory table, if the Truck is passing the City, State = Passed and if it gonna stays for ...
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1answer
84 views

Database Normal Form (financial statement)

I would like some advice on how to design the database for financial statement data which objectively addresses the tradeoffs between usability, performance, maintenance and adherence to normal form. ...
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94 views

Associating on the ID of an association table

Sorry about the title, I couldn't find anything better. Suggestions are welcome. Say we have two tables, Suppliers and Products. The same product can come from many different suppliers, so we create ...
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35 views

Schema/Structure to handle secondary computed data

I'm trying to design a LAMP-based website for my pinball league, which plays competitive pinball every week in match play. One of the features of our league is that we convert raw scores to ...
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123 views

How to design tables for airbnb style booking system

all. My English is not very good, but I will try to describe my question as clear as possible. I want to design a airbnb(https://www.airbnb.com) style booking system, this kind of booking system ...
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71 views

schema for mysql database with 30million rows

We am building a SaaS backend for restaurants. We integrate directly with POS, so each POS keeps sending customer orders that we store in a following table in mysql. CREATE TABLE name ( `id` ...
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1answer
105 views

Normalized Data Store - Confused with prefixes to use

I'm designing a Staging+NDS+DDS Data Warehouse system, where an ETL is going to normalize data from [Staging] and load it into [NDS], which will hold all history. I've pretty much finished the T-SQL ...
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1answer
209 views

Dependency preserving and lossless join decompositions

I have a relation: R = {A, B, C, D, E, F, G, H, I, J} And a set of functional dependencies: G = {AB -> C, A -> DE, B -> F, F -> GH, and D -> IJ} I ended up decomposing into two ...
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1answer
36 views

Database table to keep track of objects

I have a table called FoodMaker and another table called Settings. Every FoodMaker has multiple Settings. I also need a 3rd table to record what has been made, when and with what Settings. It might ...
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51 views

identifying the functional dependencies

I have been reading up on database design and I am having some difficulty constructing functional dependency diagrams from tables. I have the following table. Each salesperson is identified by a ...
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29 views

why this FD make 3NF?

Question like this: Consider the relation scheme ABCDEF satisfying the following functional dependencies: BC --> ADEF CD --> B E --> D BC is a key and designated as primary. Explain why the ...
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50 views

Table design for optimum performance

For example let's say I have to create a table called Employee with columns EmployeeID, Name, DOB, Address, DepartmentID[FK]. So I create the table as follows with a primary key and a nonclustered ...
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With SSD's and in memory tables, does a snowflake schema become preferred over a star?

With SSD's being very fast (reducing the overhead of joins), while more expensive (increasing the cost of redundancy due to de-normalization), along-with a focus on in memory tables (again reducing ...
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1answer
49 views

When using underscores, should they be reserved to junction tables? [closed]

Say you have the following tables company (contains companies) industry (contains industries) company_type (contains company types, e.g., Public, Private) company_status (contains company statuses, ...
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29 views

Advice on table structure change

I am in the process of converting an Access application that stores and reports evaluations to being web-based using php and mysql. I have converted the structure and data over from Access and I have ...
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316 views

Can't convert this type of ER diagram into SQL or relational tables

I have stumbled upon a problem during database design. Let me explain what it is all about: Contract has some simple attributes that describe him, and may have annexes and dynamics of payment. ...
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47 views

Calculate Quantity On Hand By Location

How can I calculate quantity on hand by location and validate the proposed location quantities against inventory transaction? Currently, I do not track location. I calculate total QoH via the ...
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61 views

Looking for a recipe to merge multiple rows to single row

I have a aggregation table that is written by multiple processors (around 20). Each row has a composite key - location-id, campaign-id,... and aggregate stats about it. I need to merge the ...
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62 views

Will switching from Concrete Table Inheritance to Single Table Inheritance improve the performance of my queries?

I currently have an application that allows people to view and share 10 different types of posts (ex SportsPost, WorldNewsPost, TechnologyPost, etc). All posts types are conceptually the same, but ...
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137 views

Autoincrement Primary Key For Constants

We are having an issue that is probably due to some poor design choice or lack of understanding of how to use primary keys. We have a simple constants table CREATE TABLE IF NOT EXISTS `constants` ( ...
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2answers
99 views

Need help designing a database

We are designing a system which holds statistical parameters about a particular user. As the users use the system the statistics change and the updated statistics are stored in the database. So for a ...
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1answer
55 views

Should I create a Factless Fact Table or Denormalise my table

I am creating a data warehouse from a store database and I have a question regarding the design of my dimensions and facts. In the store database a table exists for Person, Person_Address and ...
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101 views

How can I design this database?

So I have a ton of transaction logs in pipe-separated format spread across a few dozen files. Concatenated into one file, it's around 2.4 million lines. Each transaction has a store number and a ...
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74 views

A simple question regarding database design that has always bothered me

Say I have a table of schools, and each school is either Public, Private, or For-Profit. As well, each school is either '2-4 Year,' '4+ Year', or 'Graduate'. My initial instinct in this situation is ...
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2answers
167 views

How to store immutable, unique, ordered, lists?

I have an entity with millions of instances. Each instance has to reference an ordered list of items. The lists have to be unique so no list will be stored more than once. But once created, both lists ...
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38 views

Design: Fitting variable hierarchy of text files into a relational db

I have a large data corpus (several TB) made up of data gathered through customer support queries. I've been asked to set up a database to make this data more accessible, but as I'm kind of new to ...
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56 views

Using triggers or php code

I have a table called Salons, which has over 15k Salon names. I have another table which takes count of the pageviews of each salon. My question is that if I want to update reputation of the Salons ...
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38 views

How to apply updates in a “Fan out on write” architecture?

If I copy certain writes to different tables for faster read performance on certain queries(fan out on write), how should I design updates? Since the data is spread over different tables, I'm trying ...
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1answer
67 views

Division Email Template DB Design [closed]

First question for me on the DBA SA site! This is for an Java email notification app using MySQL for backend. I have a small number of groups in our organization, [Marketing, Commerce, ...
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45 views

calculating Canonical covers

Given F = {AB -> C, A -> BC, B-> A}, compute Fc AB-> C is A extra? {B->C, A-> BC, B->A} 1st possible Fc = {A->BC, B->AC} AB-> C is B extra? {A->C, A->BC, B->A) 2nd possible Fc = {A->BC, ...
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34 views

Tables with same schema in DB for different sources. Bad pattern?

The main purpose of the system being developed is to collect data from different sources, process and standardize it, and then add it to the DB. After information from all sources is collected it ...
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1answer
47 views

How can I quantify the business value of normalization?

My company is developing an internal application with a SQL server database which was started earlier by another developer. Now I am Looking at the model,the developer has stopped at 1NF. I proposed ...
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1answer
98 views

Date model for commenting system stored in a key-value NoSQL DB?

I'm trying to leverage Cassandra's strong support for time series data to build a commenting system. So far I'm thinking that each row would be a particular topic, and each comment would be a new ...
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1answer
28 views

Financial Inst - Model Role+Relationships b/w Person and Account

A Person can be on one-or-more Accounts. For each Account a Person is on, Person has a certain role on that account i.e. Person 1 is primary on Account 1 Person 1 is joint on Account 2 Person 1 is ...
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1answer
245 views

Postgres JSON field for many to many relationships

I'm designing a schema that has a many-to-many relationship as such: A lead can have several stages and each stage can have several leads. I currently have three tables, with one of them as being a ...
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73 views

Best way to handle multiple query keys

I am designing a postgresql database for an online card game. I want to provide users with the option to access their play history - users can see log of their games. The data I want to save has the ...
2
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2answers
966 views

Check whether empty strings are present in character-type columns

I have an application that (as part of its logic) trims strings and replaces empty strings with NULL prior to insertion in the database. I guess one way to ensure that this is enforced would be to ...
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1answer
82 views

creating a multi table “identity” column (faux identity)

I am currently designing a job execution engine and have run into a problem I am looking for some advice on. I am converting some processes to a new system and need to define the table structure. ...
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56 views

Billion records mysql performance with large result sets

I'm currently developing an application which will have several mysql tables where 3 of them have very large amounts of records. The thing is that my app will have to sync each account on a hourly ...
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1answer
122 views

Best design to handle multiple query keys [closed]

I am designing a postgresql database for an online card game. I want to provide users with the option to access their play history - users can see log of their games. The data I want to save has the ...
0
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1answer
54 views

modeling data dimensions as columns - some dimensions are highly variable while others have low variability

Please excuse my question if it is a bad one - I am not a DBA... I would like to model the following data: Let's say that I have one column that is the row id as generated by a sequence. Let's also ...
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44 views

A many-to-many relationship

I'm designing a simple database and have a question regarding a relationship. So far, I have users, books, highlights and bookmarks. The relationship rules are as follows: Each user may 'subscribe' ...