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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346 views

SQL order by query results in any arbitrary (but reproducible) manner

For testing purposes I need to get some data from a set of database tables in any arbitrary (but reproducible) order. The idea being that I can later compare two runs using a textual diff tool. Is ...
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1answer
426 views

Multiple User Types - DB Design Advice

I'm developing a web application that will support user authentication with corresponding roles for each user. Also, my users can be of different types and have different fields associated with them. ...
1
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1answer
127 views

Complicated data

I have a requirement i got from my father. He gave me a table and wanted me to digitalis it. So that he can the system can do all the dirty jobs for him ( that's why there are developers in the world, ...
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2answers
5k views

Disable all constraints and table checks while restoring a dump

I've obtained a dump of my PostgreSQL database with: pg_dump -U user-name -d db-name -f dumpfile which I then proceed to restore in another database with: psql X -U postgres -d db-name-b -f ...
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0answers
1k views

Need Help in DFD Diagram for online hotel booking system

Hi friends, I am creating a data flow diagram for online hostel booking system. not sure if i created a correct diagram or not any help would be appreciated. thanks in advance
2
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1answer
62 views

Best way to design a database with one person with different roles

We've been browsing for a while looking for an answer to this, but any of them suited exactly my needs, I hope is a relevant question. We have a database for managing books. In this database, a same ...
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3answers
74 views

Best approach for Legal/Natural can have many Orders

I'm working on this model: where as you may see one NaturalPerson can have many Order and the same for LegalPerson the only difference between NaturalPerson and LegalPerson are a few so in that ...
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1answer
445 views

Calculating a running balance to store with transactions

I need to put a read-only copy of balance and transaction data from a legacy system, which will only be used to view/print statements. Balance | id | member_id | product_id | balance | | 1 | ...
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2answers
3k views

Online Hostel Management System ER Diagram

I have created an ER diagram for an online hostel management system. Please advise me if this diagram makes sense or needs improvement.
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2answers
158 views

How to architect an analytical BI platform? [closed]

I am working on a new BI project for a medium sized corporation. Right now there is no Analytical infrastructure in place and the reporting is done manually in Excel. There are a few different data ...
5
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1answer
130 views

Many-to-many relationship with attributes

I'm working on a project where I need a book database. The problem is as follows: A book can be related to multiple people (authors, editors, traslators, etc.). Then a person may contribute to ...
0
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2answers
158 views

How to store user's language knowledge (150+ languages) in mysql DB

Users in my website must be able to select languages they know (English, German, etc), so I have a table languages with 150 languages (id, name) and table users (id and a lot of other fields). ...
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3answers
348 views

Removing chat history for a particular user from database

I'm currently developing a web chat application using SignleR and SQL server this is my database schema so far I've added an option where the user can Clear Chat history for a particular ...
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0answers
60 views

Oracle 11 table design for better performance for reports?

We have a requirement to design a report page. A few factors we have are: number of fields in report is 70 computed fields is going to around 14*8 (based on toggles) a filter is going to have ...
2
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3answers
253 views

Tracking events in a task database

In designing a task database with the usual set of tables (Users, Tasks etc), I'm wondering if there is an accepted way to track changes to fields in the task table? I could just provide a text log ...
7
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1answer
229 views

Adding nullable column to table costs more than 10 minutes

I have problems to add a new column on a table. I tried to run it a couple of times, but after more than 10 minutes running, I decided to cancel the query because of lock time. ALTER TABLE mytable ...
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1answer
41 views

Should I drop this column or is there a query that can achieve a results table without duplicate columns?

I use a column named active in several of my database tables to adjust whether a particular entry/row/user/etc should be included in future query result tables instead of deleting the information. ...
0
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1answer
30 views

Separation of users columns in another table

I've got a quite a lot of columns on the users table and I have been cleaning it up recently. Now since I'm searching over the users I figured it would improve performance if I separated verification ...
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0answers
18 views

How to model mappings at various levels

I'm trying to design the database model for my application and I'm finding it difficult to design the mappings for user access to various entities stored in the database. If access was only ...
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0answers
118 views

Storing DB credentials in an application source code?

I am making an app which connects to a DB, and the app will have plenty different userslogins. Is it a good design choice to have a specific DB login/password for the application, using which the ...
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1answer
179 views

Unique constraint to enforce max one null per item

I am using PostgreSQL 9.3. Suppose we are manufacturing some items of certain types, at any moment we are producing at most one item of a certain type. The following table captures our history of ...
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0answers
68 views

Relational or non-relational database for a system to pass objects on?

hopefully this is the right place to ask this kind of question. I am working on a system that focuses on helping people give away things that they don't use anymore. So, an object typically has the ...
0
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1answer
56 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 ...
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0answers
53 views

DB design, when to split out into schemas

I am building a storage solution to store important themes/concepts referenced in books. At a high level the system will contain one or more catalogs and each catalog will contain one or more books. ...
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3answers
69 views

How to design database with january-december for every entry [closed]

Need help for designing my database, I have a table named transaction with columns: tr_id, item, item_cost, item_quantity, total and my problem is: I need to divide the item_quantity from january to ...
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0answers
16 views

How to test if a model is erroneous?

i am trying to realize why the following model is erroneous(or not). i am taking a database course and while i was studying I've found that model.
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2answers
49 views

Schema for storing historical data on shared identifiers

When user account is assigned an IP address, I create a table entry for the account/IP mapping. This data in the table is updated every 5 minutes. Right now I'm only keeping real-time data but I need ...
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2answers
55 views

What database should I use? [closed]

I am writing a log analysis program in bash. As part of it, I am compiling a list of known errors, so that I can search and reference those errors as part of the known list. I originally was going to ...
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2answers
242 views

Need Help maintaining multiple databases for a multi-tenant application?

i need some information about multiple databases for a multi-tenant application ? I am working on a project in which we are maintaining separate database for every company? The Companies Database ...
5
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2answers
73 views

How to enforce the structural constraints of rectangularly arrayed data?

(I'm particularly interested in answers that view the question below as a special case of the question: how should a RDBMS enforce structural constraints that are more specific than "one-to-many" and ...
0
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2answers
448 views

How to break table into two without losing performance?

According to http://stackoverflow.com/a/174047/14731, splitting away infrequently-needed columns frees up the cache allowing faster retrieval of the commonly-used columns. I've got a table whose ...
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1answer
61 views

Does a Key-Value type table still needs a auto increment key?

Suppose that I have a very simple table to store variable-like data, like this: +-----------+-----------------+ | key | value | +-----------+-----------------+ | site_url | ...
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0answers
231 views

How to handle many columns / variable schema?

I apologize in advance in case this question has been asked already. I'm working on revamping a reporting application used within my company. The requirements are: Support addition of new fields ...
2
votes
1answer
74 views

Hierarchy for dimensional model

I am trying to model a DW where I have many levels of geography (Neighborhood, District, City, State). I have several demographic data that should be included in the model. These data include count ...
0
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1answer
848 views

Max from 2 columns with priority date col then the seq col Oracle

I have a column xdate, column seqnumber, personID I want 1 record per personID, where it is the most recent xdate max(xdate) if there is multiple same max xdates i want it to look then for the max ...
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0answers
41 views

Minimize table joins in design

Probably didn't come up with the best title, but I'll explain what I'm trying to do. I need to be able to track gym members, trainers, workouts, and gym locations. I've created a simple example below. ...
0
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2answers
55 views

Null column for username and password when using Login with *social network*

I want to know what are the conventions for columns like username and password when your application supports login with a third party, like login with facebook for instance. Given the fact that when ...
3
votes
4answers
247 views

How do I prove that the act of removing foreign keys doesn't corrupt existing data?

TL;DR: Prove that in practice, the execution of the alter table table_name drop foreign key constraint_name statement does not corrupt existing data. The important consideration is the execution of ...
0
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1answer
94 views

How do I choose primary keys for star schema BI data warehouse?

I am extracting sales turnover data from a Microsoft Dynamics Database into another SQL database that will be used by the BI tool of choice. This data is coming from G/L (general ledger) entry items. ...
0
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1answer
125 views

Schema for multi-account database

I'm building an app which will have accounts for organisations leading to organisation.myapp.com subdomains for their account access. I'm putting together the schema for it and I have a few ...
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0answers
45 views

Optimal layout strategies for Time-Series using Columnar storage

In the context of time-series and specifically columnar storage systems. Question: What are the processes or heuristics that are used to determine how best the columns of contiguous values be grouped ...
5
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1answer
437 views

Bad Design or Complicated Query?

Problem: For fun I am building a Database for lottery results to get some statistics off of. As of now I am only interested in a Pick 3 style lotto and might introduce more later. How would you ...
0
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2answers
287 views

1 million strings and exact match search

I need to chose the best solution (software and algorithm) to solve my problem. I need to store up to million strings and data associated with them. Strings are search queries and data is cached ...
0
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1answer
2k views

Converted ERD into Dependency Diagram 1NF, 3NF

Thats the ERD. I'm studying for an upcoming test and having trouble getting my head around converting thes ERDs into dependency diagrams. This is from a previous exam that the Lecturer told us to ...
3
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1answer
306 views

Building a branched versioning model for relational databases

I am database designer and at my current project I'm implementing versioning capabilities required to concurrently edit rows of data in RDBMS. The project requirements says, that data editing sessions ...
0
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1answer
27 views

Establishing referential integrity in a generic table?

Current Schema: - DropDown: DropDownID PK, Name nvarchar(25) - DropDownOption: DropDownOptionID PK, DropDownID FK, Name nvarchar(25), Description nvarchar(155) ...
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1answer
54 views

modelling warehouse picking

What's the best way to approach modelling a warehouse picking system? To be precise, customers place orders which are processed by warehouse staff. A simple products and orders database isn't an ...
2
votes
1answer
202 views

Which is the better schema design for a voting system?

Imagine a q/a site or forum similar to stackoverflow. I'm trying to determine which of these two methods would be the better design for a voting system: (note: I would also like to keep record of all ...
8
votes
2answers
178 views

Should I add transitive foreign keys?

Simple example: there is a table of customers. create table Customers ( id integer, constraint CustomersPK primary key (id) ) All the other data in the database should link to a Customer, so ...
0
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0answers
40 views

Conditional value lists in MySQL

apologies in advance if the language I use here is insufficiently specific. Please let me know if there's anything that I can clarify. Does MySQL provide a means of creating conditional value lists a ...