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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Database throughful design vs Quick and dirty design comparison

Take the representation of an Address, here below is a complete and very detailed implementation: here instead is a quick implementation (which more or less contains the same fields, imagine all ...
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98 views

When to use hashtable over binary search tree vice verse for Database Index

Database Index can be constructed using binary search trees (BST) or HashTables , From my understanding so far , HashTables are superior to BST in terms of time taken for searching and insertions ...
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341 views

Most efficient queries on flags in TSQL: bit field or table join?

Looking for the most efficient database structure for selecting rows from a large table based on one or more true/false values. For example, whether or not a user has opted in to marketing ...
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145 views

Most performant way to fetch last record

I have a Postgres table Prices with the columns price (Decimal) product_id (Int) Prices get updated regularly and I keep old prices in the table. For a given product, the last price in the table ...
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1answer
141 views

Enforcing constraints “two tables away”

I ran into some trouble modeling an electrical schematic in SQL. The structure I'd like to capture is part ←────────── pin ↑ ↑ part_inst ←───── pin_inst where "inst" is short ...
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68 views

How to structure a database to show data for each USA State and Canada Territory on a Per user basis?

I need to build a PHP/MySQL application. I am a bit confused on how to do the database for a project like I am about to explain though. The end result will be a Map of the USA and Canada. Each ...
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136 views

Digital content eCommerce schema advice? [closed]

I don't have much experience designing databases, I'm looking for some advice on my design from more seasoned designers/developers. I'm developing a digital content eCommerce store which will be ...
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2answers
124 views

Does this medical database look correct?

I'm pretty new to databases and I'm trying to create some schemas. I've been working away at this one for a while, but I can't help feeling that it doesn't look right. Essentially I have the ...
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1answer
366 views

What is a bucket in database? [closed]

I was implementing a code that involves a database and buckets. Just wanted to ask what is bucket and can someone describe it with an example? Thanks!
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25 views

Impact of additional int field as primary key

Directly to the point, at one time I have a table like this: create table item( item_id varchar(50), constraint pk_item1 primary key (item_id) } However from my discussion one day, there is ...
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1answer
52 views

Denormalize Design Modification

Our DBA is on medical leave, I am just a developer trying to do my part. Initially, the bean counters were going to use quickbooks. However, after seeing how much time they could save with custom ...
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1answer
135 views

Best way to store an unordered list? [closed]

I apologize if this question has (undoubtedly) been asked before, however I've been hearing conflicting advice from colleagues and the internet. I have a table of "groups" and each group has a list ...
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2answers
153 views

mysql forbidden database names

I was wondering whether there were a list of forbidden (reserved) database names in mysql. For instance, mysql is obviously one. But is there a determinated list? I don't want to cover 99% in my ...
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1answer
93 views

What Happens when Cartesian Product is applied to Relations with same attribute name

I understand that the Cartesian product(X) operation on two databases does not need to be UNION compatible.So,if there is a same attribute called name in the two relations R and S where name in R is ...
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3answers
280 views

Why does data get corrupted in “large” text files - Reasons to use database

I am just starting to learn about databases and using mysql. I read that databases are more reliable than having large ascii text files and that ascii text files are more prone to corruption as they ...
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1answer
32 views

design DB review and check constraint for postalcode help?

Hi. I created this database to just to sharpen my skill. I have one Question - when I create I make the FOREIGN KEY personID in Addresses table but I changed it to be AddressID in Persons table ...
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498 views

Should I place my Quartz Scheduler tables in a separate database?

I am designing a web application that uses Quartz Scheduler to scheduler jobs. I have Quartz configured to use a JDBCJobStore, so it automatically stores each created job in its tables. I am ...
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126 views

Can somebody check this normalisation workings i think i am missing a step or a dependency somewhere

given these two tables: and: I need to first list them as an un-normalised structure(s) then i need to identify the functional dependencies/primary keys. Once i have done this i must represent ...
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1answer
91 views

Recipe Health risk Database ERD structure

I have these tables: First table(Recipe table), Recipe recipeid(PK,AI) recipename ingredients Second table(Ingredients table), Ingredients ingredientid(PK,AI) ...
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2answers
226 views

Is there a well-known name for this “poor man's ref. integrity” schema design pattern?

Is there a name for the following database schema design/pattern? My eventual goal is to find more literature about the subject. Today's cursory net search was too full of generic words to be able pin ...
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275 views

Hierarchical structure with limited number of records per user

I am planning schema for an affiliate network. For all hierarchical queries I am using Postgres tablefunc extension but here is another problem. Any user can refer only 3 other users at max. So for ...
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2answers
208 views

Can somebody help me normalise this database/check my workings

I am new to database design/normalisation and functional dependencies. I have started a new database class in school this week and we have been given a worksheet that requires the following: This is ...
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1answer
108 views

Combine or Separate Tables

I have a single table that holds the following data columns: id = Auto Increment provider = Twitter or Facebook (depends what they use to login with) uid = User ID name = Their full name (e.g. ...
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118 views

How to join the tables in mysql to get wall messages and comments with name of person ? Only user and his friends messages

I have four tables in my mysql database as shown in the image url provided. I want to select data from the tables without duplication. I want to show messages and comments on wall according to the ...
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8 views

Source control makes sure my code is never lost, how do I make sure my users/orders database is never lost?

Everyone is recommending the use of git, automated tests, continuous integration, automated deployment and so on, to reduce human error during all stages of web development. I have yet to come across ...
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1answer
360 views

Functional dependencies and candidate key example [closed]

Hi there I'm still learning for my examination and I got this exercise: A table is given: F-Name, F-Nation, Team-Name, Team-Nation ...
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1answer
174 views

Schema for a Soccer club

I am designing a database for a Soccer club. A soccer club has several teams. Those teams have several players and a coach. Right now I have three tables: Club Team (foreign key to club) Player ...
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823 views

How to handle table design with variable columns

I have a table design scenario and as a non-DBA type, would like opinions on which is more scaleable. Say you are asked to record information on houses for a metro area, starting with a small ...
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eCommerce orders table. Save prices, or use an audit/history table?

Im designing my first eCommerce schema. I've been reading around the subject for a little while, and am a bit confused about the relationship between an order_line_item and a product A product can ...
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2answers
165 views

Data Modeling for different roles

This is my first post here, so I hope its clear enough. I want to make an application for people who sell, buy, rent and fix a certain product. I need to create a database that would keep the data of ...
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56 views

Calulating savings between two schemes

I've normalized a single table to reduce the number of nullable columns from 3 down to 0. The idea was to save a little drive space but I'm seeing a 45% decrease in space needed to store the same ...
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1answer
106 views

Table design for departments with duplicate department numbers

How should I define a database table for my company's departments where we have a set of duplicate department numbers used by an upper management tier. dept_id dept_name manager_id ...
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115 views

Using MySQL As A Graph Database, Can It Be Done Efficiently?

So I am currently working on a startup idea with a friend and we've come a long way, it's somewhat functional and I've tried to not let database design decisions slow the progress of the site. As of ...
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223 views

Normalizing data to 3NF

I need some help with normalization. Here is the data in 0NF : **HOSPITAL SERVICES (date_hospitalization , id_patient , id_doctor , name , surname , PIN, duration_of_hospitalization , ...
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161 views

How to model complex database role relationships

The purpose of my application is the creation, viewing and editing of articles. The problem I have is that users will have different roles for an article or group of articles. In addition, the role ...
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Storing and querying rolling data in PostgreSQL

I have a large quantity of weather model data being put into a PostgreSQL database. The machine has 8 cores and 16 GB of RAM. I'm running PostgreSQL 9.3 with PostGIS 2.1. Each table will have a ...
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1answer
4k views

MySQL count multiple columns and sum the total occurrence

I have the following table, say, MyDRAW ... DRAWNO PRIZENO FIRSTD SECONDD THIRDD FOURTHD M123/14 8458 8 4 5 8 M123/14 7214 7 2 1 4 M123/14 1640 1 6 4 0 ...
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272 views

Can Anyone please review my database after I did the Normalization ?.Any suggestion is appreciated

User: User_ID,user_name,E-mail Staff: User_ID,Fname,Lname,DOB Student: User_ID fname Lname DOB Lecture: User_ID Admin: User_ID Position ID : P_ID,ROLE_NAME, Staff_position ...
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2answers
90 views

Is it important to design the database the right way from the beginning?

I'm a beginner web developer and I use MySQL and sometimes MS SQL Server. However, I don't have that much information about databases, just basic information to be able to build some tables. Now, ...
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3answers
921 views

Db Design of a Room Booking System

I plan on building a web based room booking application for meeting rooms at a company. The requirements are not set in stone and are pretty much left to me, as long as these core ones are met: ...
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1answer
70 views

Database Design guidance required

I have scenario where there is Table T with columns PK,A, B, C,D TABLE t ( PK, A, B, C, D ) i have to insert data from different sources ie columns A,B,C,D are calculated separately.. and they same ...
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224 views

Concept, ER model, “employee tracking”

I have to achieve 3NF with following specifications: Database where I will determine priority skills for specific jobs and track the employees ability to complete them. Train employees. Example of ...
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2answers
55 views

Best design for a many:many relationship issue

We have three types of entity, each with their own table: table:A(a_id), table:B(b_id), table:C(c_id) Each of these entities can have any number of email addresses and linked Twitter accounts. ...
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1answer
364 views

Autoclose property resets to true after attaching db even if model is set to false

I am using SQL Server Express 2008 R2. The auto close property of a newly created database will be set to value same as model db. In my case I have set autoclose to false for model so that when I ...
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42 views

Help with designing a multi relational schema / domain model

I am in the process of developing a web application with asp.net MVC. I am using Entity Framework to make a connection to my database. I am having trouble with a specific concept in my program. I ...
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1answer
156 views

MS Access + SQL Server for 1160 users - Is it worth it? (Please Help!) [closed]

Our school in Delhi (India) wants to develop a professional and robust in-house database (SIS) that should handle vast amount of student information, including admissions, registration, re-enrollment, ...
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33 views

Keys of a relation

I got relation: R = { (ABCDEF) , (A B F -> C, B C -> F, F -> A, F -> B, D E -> E, E -> D)} keys of this relation are: {BCE}, {EF} But i dont get it... why? Why not only {EF}.. it got less ...
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66 views

A simple database and Query System? [closed]

I am new to databases and trying to solve one problem in which I have to build a simple database having few entries and then querying that database and then recording that answers from the database. I ...
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476 views

Decomposition of a relation to 2NF and 3NF

I am trying to solve this example, but for now I can't. Can somebody show me, step by step how to decompose this to 2NF and then to 3NF? R = {ABCDEF, ABC -> EF, B -> E, E -> D} key of this ...
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1answer
131 views

design database for electrical meter data?

Hi just wondering how to I have .csv "Time 'datetime' Voltage 'double'"file that record Voltage usage from electrical meter each every minutes and database to record the data just want to normalize ...