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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6
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2answers
39 views

NoSQL : What is unstructured data?

we are currently running at the edge of resources with our mssql server based solution. We have now many traditional options regarding the next move to tackle the load: buy faster CPUs and IO ...
1
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2answers
39 views

Users vs. People - where to keep the email address?

I'm designing an app similar to Facebook, called Headtome. I want to have users that create public profiles, including email addresses. Then, Mary can choose to message John, and that message goes ...
0
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3answers
29 views

How to design a Table in which its fields varies on its categories?

I am trying to design a database to post free ads. Eg http://www.gumtree.com.au/p-post-ad.html Scenario: Every ad will have different categories and some categories will have further sub categories. ...
1
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0answers
12 views

fast execution analitycs database with thousand rows to displaying in php [migrated]

i've table with a thousand rows and i want to creating analitycs with chart display my front end php my table structure is and how i display this data : by user_agent column i display operating ...
0
votes
1answer
21 views

Slow query - just error count

I deal with slow queries in whole project. I indexed heavily but the results are nowhere. I had a lot of logs (thousands per minute) from SCADA systems and I am trying to count them for each SCADA ...
6
votes
2answers
114 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 ...
9
votes
5answers
49k views

Matching single column against multiple values without self-joining table in MySQL

We have a table that we use to store answers to questions. We need to be able to find users that have certain answers to particular questions. So, if our table consists of the following data: user_id ...
0
votes
1answer
105 views

Decompose table into third normal form

Tables X and Y are given as below : X (A, B, D, E, F, G, H, J) with A and B as primary key Y (K, L, M, N, O, P, Q, R) with K and L as primary key Now we need to decompose these tables into tables ...
3
votes
1answer
63 views

Can jsonb do fast search by *value* or even a partial value? Other types?

I have a person table where arbitrary data must be inserted. Since I'm using Postgres 9.4, jsonb appears to be the right choice. Example data: id: 1, name: "Joe Doe", preferences: { color: "red" , ...
1
vote
2answers
22 views

Suggestion for enforcing unique constraint in a table where soft delete is implemented [duplicate]

I am using SQL Server 2014 and in my database, I have a Position table which is structured like this: ID int PK Name nvarchar(50) Unique Index IsDeleted bit A ...
-2
votes
0answers
26 views

Entity-Relationship Modelling [on hold]

WWLS staff consists of lawyers and secretaries. Lawyers work on cases, while secretaries provide assistance to lawyers , while some secretaries assist only one lawyer, some of them assist multiple ...
1
vote
0answers
49 views

Schema question

I'm creating a schema for product failures and repairs and would appreciate feedback on the schema. The database is intended to capture all product failures and corresponding repairs. A product can ...
3
votes
2answers
48 views

Computed Column Update when Table Value changes

I have environmental sensors collecting some raw data from environmental stations. In addition to the sensors, there is a physical gauge measuring water height (staff gauge). I'm trying to set up the ...
7
votes
3answers
103 views

Constraint to enforce “at least one” or “exactly one” in a database

Say we have users and each user can have multiple email addresses CREATE TABLE emails ( user_id integer, email_address text, is_active boolean ) Some sample rows user_id | ...
27
votes
7answers
24k views

In what data type should I store an email address in database?

I understand that an 254 character email address is valid, but implementations I have researched tend to use a varchar(60) to varchar(80) or equivalent. For example: this SQL Server recommendation ...
-3
votes
0answers
18 views

duplicates of part.num to be summed and add another column called user [on hold]

There are 3 columns part num, Qty and MO. Each MO has part numbers.So there might be same part numbers in MO's. Each part num has qty. So, if I group by part num, I get Qty. 1.There are duplicates of ...
1
vote
1answer
18 views

Is this the correct way to model a relationship between an object which may or may not have another object?

I'm creating a database for a department store and the database has two tables: Items and Coupons. An item, like a TV, can only ever have one coupon. Some items don't have a coupon at a given time. ...
3
votes
1answer
146 views

How do completely empty columns in a large table affect performance?

I have 400 million rows in a Postgres db, and the table has 18 columns: id serial NOT NULL, a integer, b integer, c integer, d smallint, e timestamp without time zone, f smallint, g timestamp without ...
4
votes
1answer
46 views

How can I design a database to track each individual's stat changes weekly, in a group?

There is a group of people, and I need to track each person's individual numbers weekly such as their weight lost, steps walked, and bad foods eaten. I plan on implementing this database into ...
0
votes
1answer
28 views

A form including content from two tables

I am working to create a database of all the places or administrative entities of one country. Most work will be about adding new districts. I have to detail which region every district belongs to. ...
0
votes
0answers
19 views

Best practice to create a database schema for Open Auth (Social logins)

I've done a database schema for user management alongs with their roles and permissions. The problem actually began, when I decide to integrate a multiple "Open Auths" such as Facebook Login, Google ...
1
vote
1answer
99 views

representation in ms-access

I have a database in microsoft access. I want to know how to look up a singular datum from a reference table giving a dynamic set of values. Here is a representation of what I mean: I have the ...
2
votes
0answers
44 views

Networking (classmate like) website database model

I am working on a project that consists in building a networking website like the Classmate web site. I have proposed a database model based on the social media database model presented on the ...
1
vote
1answer
204 views

Optimize large table design

First, I am a complete novice when it comes to databases, but have been given the task to speed up queries on a large set of data. (Hundreds of millions of records) The current implementation is a ...
4
votes
1answer
70 views

Better database design

I'm using a MySQL database to store data from my java application. In java I have two classes: The VocabularyList class has a name and holds a list of vocabularies. A Vocabulary has a vocabulary ...
0
votes
2answers
202 views

Daily snapshot fact table

I have a list of products per costumer. Costumers can delete or add products to their list. I want to know in each day what is the list of products (and count) by costumer. My first approach is to ...
2
votes
1answer
36 views

Database schema for passing requests to role based users

I am working on a Database schema where the scenario should be: There are role based Users; Role 1, Role 2, Role 3 and Role 4 There is a Request model (or class, or table) User with role Role 1 will ...
0
votes
0answers
40 views

mysql - suggestions for table design with huge number of columns

We have a table that consists of a huge number of columns (usually between 500 to 1000, depends on our clients websites). We are suffering from speed issues due to this, and we're looking for the best ...
6
votes
1answer
504 views

ERWIN create and use database

I'm trying to generate physical database from my logical model using ERWIN 7. All is well in the script that is generated automatically, there is only the problem that the model is created in the ...
3
votes
0answers
68 views

One table or four?

I have four entities: Absence { ID, StartDate, EndDate, Days, Hours, Reason } Overtime { ID, Reason, Date (Integer), Hours (Integer) } Time in lieu { ID, Reason, Date, Hours } Holiday { ID, ...
5
votes
2answers
99 views

Which to store: miles or kilometers?

My app is launching to a US audience first, but I want to internationalize the database schema for future expansion. Obviously I will convert between the two units as necessary regardless, but are ...
18
votes
8answers
8k views

Storing IP address

I have to store the IP address of all registered users in the database. I am wondering, how many characters should I declare for such a column? Should I support IPv6 as well? If so, what is the ...
0
votes
0answers
31 views

How to make a query from a database with schemas to a database without schemas, and vice versa, with DBLINK in postgres

I have a DB (DB1) in postgres 9.4 who use DBLINK to query another DB (DB2), and vice versa, using views and functions. But now i have to add 2 schemes to DB1 (CLIENT1 And CLIENT2) and i want when i ...
14
votes
5answers
8k views

Why does a UNIQUE constraint allow only one NULL?

Technically, NULL = NULL is False, by that logic no NULL is equal to any NULL and all NULLs are distinct. Shouldnt this imply that all NULLs are unique and a unique index should allow any number of ...
7
votes
1answer
93 views

sysschedules datatype choices

I am curious, why does SQL Server save the values in msdb.dbo.sysschedules for date and times as int instead of datetime. I assume the reason dates back to something in SQL Server 2000. Was it a ...
5
votes
2answers
2k views

SQL Server database forum design sample

I am doing a design for a database using SQL Server 2008 R2, basically it is a simple database design for a forum (just like games fans forums). Fortunately I am struggling with it as I didn't find ...
1
vote
2answers
99 views

Collation by row, not by column

Is it possible in SQL Server to set collation on individual rows in a table (as opposed to by column, database or server)? If not, perhaps does anyone know if this is a planned feature for SQL Server ...
2
votes
1answer
367 views

Setting up simple question & answer database

I am having trouble thinking this (simple) table relation through. I am setting up a quick SQL DB to populate labels and textboxes dynamically on screens. This is just to prove we can do it, so it ...
3
votes
2answers
22k views

Using Same CASE WHEN Conditions For Multiple Query Columns

Is there a "better" way to rewrite a SELECT clause where multiple columns use the same CASE WHEN conditions so that the conditions are only checked once? See the example below. SELECT CASE ...
8
votes
9answers
2k views

Which DBMS are fast enough for an online game (few thousand players)?

I'm currently making an MMORPG game, which could have a few thousand players online at the same time (probably not; just wishful thinking). First we wanted to use MySQL, but I have heard it isn't fast ...
0
votes
4answers
766 views

Why Clustered Index property is enabled on few columns and not on others?

I heard that there can be only one Clustered Index? I may be wrong, but I am sure I read somewhere. In one of my SQL Server 2005 table, I have following columns: SerialNum ------- BigInt -------- ...
1
vote
1answer
234 views

Resolving Cyclical Reference in Referential Relationships

I'm designing a small SQL Server Compact Edition database and am attempting to enforce referential integrity. The database is a simple backend for a small desktop application that functions as an ...
2
votes
2answers
834 views

Design best practices for last tracking with indexed view

My tables structure is below : TbDoc (ID int , ...) TbDocActions( ID Int, DocID Int, Date DateTime, col1 int, col2 int, ...) I want to have indexed view to get last TbDocActions columns for ...
1
vote
1answer
26 views

Index design question

This query runs for 60 seconds: SELECT mychecklis0, .... FROM dbo.MyChecklistStatus mychecklis0_ WHERE mychecklis0_.AppFormSubSectionId=@P0 AND mychecklis0_.ProfileId=@P1 There is an index created ...
8
votes
2answers
1k views

Data Warehouse design for reporting against data for many time zones

We are trying to optimize a data warehouse design that will support reporting against data for many time zones. For example, we might have a report for a month's worth of activity (millions of rows) ...
5
votes
1answer
835 views

Database table design question

Firstly, database novice here. I'm trying to create a system for processing Sales Orders into Purchase Orders and then split the Purchase Order into Shipping Containers. The systems needs to be able ...
1
vote
0answers
23 views

Search a value from multiple column and multiple table [closed]

I have to search a value from multiple column and multiple table and each table is linked by foreign key and private key (in parent table , there is only one parent table and rest is child table of ...
5
votes
2answers
138 views

Storing a Billing Address Best Practice in Orders Table

Can someone help me understand this user's answer for a CustomerLocation table. I really want a good method for storing addresses in the orders table. What I'm looking for is how I can set up my ...
1
vote
1answer
315 views

Difference between Relational database and time series database?

I have a bit stupid question maybe. I recently came across a term "time-series database". I would like to ask what is time series database and is it same as relational database? Thanks,
3
votes
1answer
1k views

Designing a reservation system schema

I am not sure if this has been asked before, however I am tasked with designing a new reservation system for my organization We have an older system which simply stored the booking in a table, and it ...