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

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1
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3answers
49 views

Relational tables with same content, custom solution

So let`s say that I am building an app where I can add comments for FOO. Normally I would have something like this: Table foo and table foo_comments, where foo_comments contains id, foo_id and other ...
1
vote
3answers
88 views

Avoid repeated traversing of hierarchical data when parsing a big tree frequently

I have a hierarchical/tree data structure in Oracle/RDBMS where I need to traverse the tree frequently. The tree is huge and therefore parsing it every time will not be efficient. A better way could ...
1
vote
0answers
7 views

Conditional relationships? One-to-many relationship using a pivot table for only a type of entity

I have the following tables: users: - id - name - user_type_id (references id on user_types) neighborhoods: - id - name homes: - id - house_number - neighborhood_id (references id ...
1
vote
2answers
29 views

Dynamic script to Drop Indices of a specific column

I´m currently writing an SQL script to update our database and for that I need a script to drop indices that rely on a specific column (because I also want to drop the column). In my script I have ...
0
votes
1answer
3k views

Storing multidimensional array in MongoDB

I am attempting to convert a large MySQL database of product information (dimensions, specifications, etc) to MongoDB for flexibility and to move away from the restriction of a column based table. I ...
0
votes
1answer
115 views

MySQL Circular Replication

I have this scenario where I have 4 MySQL servers (A,B,C,D), as this: Server (A) is always online, and serves as the main website. Servers (B,C and D) are online on random periods of the day, and ...
16
votes
4answers
18k views

What is an audit table?

What are audit tables? How are they useful? I came across them reading this article.
0
votes
1answer
21 views

Checking for BCNF in a relational database through FDs?

Okay so I know that for BCNF, when listing all non-trivial FD's that everything to the left has to be a candidate key. So I have this relation: Person(Id, TFN, Name, Phone) Where Id and TFN(Like ...
10
votes
2answers
10k views

How to choose a collation for international database?

I'm designing a database which will store data in different languages (using UTF-8), so I think the best way to display the query's results is ordering it according to the user's language during the ...
0
votes
1answer
119 views

Zerofill Auto Increment - mySql

Ok, So I'm working on an app and I can't remember, for the life of me, why I set a zerofill on an Auto_Increment column when I created the database. And I couldn't exactly find any compelling info ...
1
vote
1answer
117 views

What Is the Next Best Ingredient to Add?

I am building a program that allows users to optimize their grocery shopping so they can make the most recipes using the fewest ingredients. One of the features of this program is a function I’m ...
3
votes
1answer
70 views

Basic question: Simplest way to share company databases

My company is looking to access large quantities of data from another company we have good relations with. Currently we are using a web interface to interrogate their information, however it is quite ...
0
votes
1answer
26 views

Raise Multiple Exceptions Postgres

I am using Postgres 9.5, and I am trying to create exception handling in a stored procedure/function. I can't quite figure out how to raise the error should any of the 'INSERT' statements fail. If ...
1
vote
1answer
42 views

Setup MySQL Master to Master replication/automatic failover when each Master also has a Slave

Thanks in advance. I have always worked with SQL Server and never really had any exposure to MySQL. I now have to determine the preferred setup for MySQL when there are four servers involved. ...
0
votes
2answers
146 views

PostgreSQL surrogate keys: use sequence/bigint or OID?

I'm looking at a need for surrogate keys in tables I'm designing on a PostgreSQL-derived DBMS (Citus). Would OIDs suffice? Is there a downside to using them instead of creating a bigint field and a ...
8
votes
1answer
137 views

Overcoming the SQL Server Express Edition limitation

Microsoft SQL Server 2014 Express edition has a database size limit to 10GB. Now, is that just for a single instance or the overall size that the edition will allow? Or does that means that I can have ...
0
votes
0answers
39 views

Store and work with current state of database [on hold]

I have a database with product, resource and planning data. The idea is to create a copy of the current data (just a part of the whole database) and then do some kind of planning-poker with the ...
0
votes
0answers
31 views

DB design: Store data VS more complex DB changes

This is my current DB structure. -- -- Table structure for table `prods` -- CREATE TABLE `prods` ( `prod_id` int(11) NOT NULL, `prod_name` varchar(255) NOT NULL, `prod_aaa_id` varchar(255) ...
0
votes
2answers
1k views

Which is the redundant relationship in this ER Diagram and why?

Which is the redundant relationship in this ER Diagram and why? A few of my friends and I have been trying to figure it out but keep going in circles. where the attributes of each entity are as ...
2
votes
1answer
112 views

Storing Friendships: Should I use a multivalued column to retain Friend Identifiers?

Say I have a table UserFriendlist that has the columns: Id (set as Primary Key) UserId FriendListIds And let us suppose that it holds the following values: ...
5
votes
2answers
67 views

Postgres Update Limit

I'm curious if Postgres has anything in place where I could limit the amount of rows kept for a ID. For example, say I have a users table and login_coordinates table. Every time the user logs in, ...
4
votes
1answer
46 views

Is my implementation of type/subtype design pattern (for mutually exclusive subclasses) correct?

Introduction In order for this question to be useful for future readers I will use the generic data model to illustrate the problems I face. Our data model consists of two entities, which shall be ...
3
votes
0answers
52 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 ...
75
votes
7answers
19k views

Why shouldn't we allow NULLs?

I remember reading this one article about database design and I also remember it said you should have field properties of NOT NULL. I don't remember why this was the case though. All I can seem to ...
0
votes
0answers
45 views

Using the same tables for multiple many to many relationships

I currently have a project where I need multiple Many to Many relationships some of them are roughly and I started to wonder if using an extra column on the table to specify the table it's related to ...
4
votes
3answers
207 views

Maintaining integrity between 3 tables when reference could be through or direct

Say we have the following 3 tables: tUsers (ID, name, countryID, regionID) ------ 1 | Joe | 1 | 1 2 | Sue | NULL | 2 3 | Bob | 2 | NULL 4 | Amy | NULL | NULL tCountries (ID, ...
0
votes
1answer
31 views

PostgreSQL values to unique dictionary

I have table with one billion rows and more than 50 columns. I need to reduce size and speed up queries, backup, exports, etc. Some columns contain f.e. only hundreds of distinct values which are long ...
0
votes
3answers
106 views

Best name for link table [closed]

I was wondering what the best name for a linked table in this situation (or any) would be. I've searched for this, but could not find any concrete examples. For example, I have the following tables ...
0
votes
1answer
197 views

How to manage very large amount of data in mysql

I have a table in MySQL in which I write logs of users in a specified format. It have just 2 columns:id (auto-increment), log. Currently data is very less, so I'm using this. Now there is a ...
1
vote
2answers
30 views

Scalable way to track who's viewed a post? [closed]

I'm building an app that needs to check who, out of millions of users, has not received a post. If a post hasn't been seen by many people, this task will be easy. But if a post has been seen by nearly ...
-3
votes
0answers
16 views

Creating a Known Error Database [closed]

I was looking for some insight in creating a simple KEDB. At first, it needs to store a simple solutions. It will have web interface.
0
votes
1answer
183 views

How to predict the growth of a PostgreSQL database

I'm looking for a way to predict growth of the database given its fields, indexes, constraints (as foreign key), number of lines, and so. I searched on Google, but I found only means to determine the ...
14
votes
3answers
1k views

What is the optimal data type for an MD5 field?

We are designing a system that is known to be read-heavy (on the order of tens of thousands of reads per minute). There is a table names that serves as a sort of central registry. Each row has a ...
1
vote
1answer
53 views

Composite Primary keys and auto increment?

i'm developing SaaS app with multi-tenancy, and i've decide to use single DB (MySQL Innodb for now) for client's data. I chose to use composite primary keys like PK(client_id, id). I have 2 ways ...
1
vote
2answers
97 views

Need advice on database normalization

I am working on a basic blood bank database on Oracle. I would like to create a completely basic normalized table and then I will add more details to it. I have done it to the 2NF and I will further ...
-3
votes
1answer
30 views

Database engine disk access [closed]

Do you know what is the difference between the database engine get rows in a table without and with use of an index in a disk prespective. They way the engine access the table in disk is the same when ...
9
votes
5answers
1k views

How to hide/disable tables without dropping them to check redundancy?

I have to maintain and extend an old legacy system which contains webservice methods and database tables that are no longer used. Since I’m not entirely sure that the tables are really redundant, I’m ...
2
votes
0answers
68 views

High Performance Relational DB for Fast Read and Fast Write [closed]

I am looking for the best database solution for a high availability, high performance solution that meets the following requirements. Data being read, written and updated is very simple, and small. ...
20
votes
4answers
10k views

Is nested view a good database design?

I have read somewhere long time ago. The book states that we should not allow to having a nested view in SQL Server. I am not sure the reason why we can't do that or I might remember incorrect ...
0
votes
0answers
33 views

Should I break up this MySQL table?

Existing table (more or less). It has about 1 million rows: id article title stage 1 zipfile name stage 1 delivery date stage 1 checked date stage 2 zipfile name stage 2 delivery date stage 2 checked ...
1
vote
1answer
35 views

Database design for surveys and experiments

I have only a bit of experience in working with databases, but rather theoretically during my studies and not so much practically. I was wondering if someone could help me figuring out how to design a ...
5
votes
1answer
134 views

Data inconsistency prohibition if a table refers to another via two many-to-many relationships

I have following database design (by => foreign key constraints are depicted): Company[id] CompanyRealm[id, company_id=>Company.id]many2many Project[id, company_id=>Company.id] ProjectRealm[id, ...
7
votes
3answers
484 views

Implementing versioning system with MySQL

I know this has been asked here and here, but I have the same idea with a different possible implementation and I need some help. Initially I had my blogstories table with this structure: | Column ...
2
votes
1answer
224 views

How to model an “is a” relationship in an ERD using Crow’s foot notation?

I have to create an entity-relationship diagram (ERD) for an assignment. I am doing this in a particular drawing tool with the Crow’s Foot notation. There is however one thing I cannot figure out: ...
0
votes
0answers
24 views

improve performance with schema design, a lot join

I'm making a custom cms system for my client, with postgresql, nodejs ... have problem with slow performance issue, when doing select data . (and it is still on localhost/mac nginx and just few data, ...
3
votes
0answers
40 views

Online text based game design - Am I linking the databases correctly?

I'm trying to recreate an old game that I used to play that went offline quite some time ago. I'm doing this as a hobby project for myself with the hope that maybe a few hundred people might enjoy it ...
3
votes
2answers
75 views

Enforce uniqueness across optional attributes for an entity

I have an entity that has multiple attributes, and these attributes are themselves entities. No two entities may have the same attributes, so there needs to be a uniqueness constraint across them. ...
3
votes
0answers
45 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 ...
1
vote
1answer
28 views

One to one relationship naming conventions

I'm designing an ER diagram with MySQL Workbench. I have two tables with a one-to-one relationship. Both tables have one column as primary key, but they don't have the same name. Take a look: But ...
1
vote
0answers
18 views

Database Design for Sports Stats

I am designing tables for tracking statistics for multiple sports like basketball and football. So my question now is - would it make more sense to design a table when both data for basketball and ...