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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What is the best way to model an invoicing system with different forms of invoice items? [closed]

I am doing some preliminary database modelling for a Line-Of-Business application that I am creating. The application will be a Practice Management System for a medical practice/clinic. I am looking ...
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Database partitioning - Horizontal and Vertical sharding - Difference between Normalization and Row Splitting?

I am trying to grasp the different concepts of Database Partitioning and this is what I understood of it: Horizontal Partitioning/Sharding: Splitting a table into different tables that will contain a ...
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211 views

facebook group alike database scheme

Here are my requirements: one user can have many tasks one group can have many task one group can have many users only invited user by a user can be added into a group Does this db design appear ...
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Two-column foreign key constraint only when third column is NOT NULL

Given the following tables: CREATE TABLE verified_name ( id SERIAL PRIMARY KEY, name TEXT NOT NULL, email TEXT NOT NULL, UNIQUE (name, email) ); CREATE ...
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63 views

Is deriving a value using multiple joins a good idea? [closed]

I am working on a university project. I need to create a database from conceptual to implementation. That allows customers to create an order with multiple products the specification says that we ...
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1answer
583 views

Relationships between subtypes of an entity

I have a very big (hundred of milions rows) table which represent an entity (event) having many subtypes (different kind of recorded events). Each row is identified by an id (obj_id) and has an ...
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1answer
527 views

Database design for threading messages

I am not sure whether this question is suitable for this forum, but since it says Database Administrator I hope I am right. So my question is, whats the database design or business logic for creating ...
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763 views

Date of birth saving to MYSQL DB with timestamp or date column type [closed]

i am using MYSQL database and would like to know which of this is a good practice. way 1 - use column type in DB as timestamp. i.e will contain values like 2012-11-13 00:00:00 way 2 - use column as ...
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117 views

To normalize or not to normalizde? (10 fields)

I'm helping someone to design a database and for a specific case I'm not sure. I have 10 fields - this will never change - that will always be filled and used in every query that could be coming up. ...
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On which filegroup will constraints be created by default when adding them to a table on a filegroup and how should they be separeated?

We have multiple filegroups, that look something like this: PRIMARY (default) app_data app_index When I create a table on filegroup app_data CREATE TABLE Person ( [PersonID] INT NOT NULL ...
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2answers
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Unable to access sql database with login and password [closed]

I'm writing Windows Service in C# and inside of it I'm unable to connect to the database. This is the question I've asked recently: SqlException: Cannot open database "path\db.mdf" requested by the ...
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Have a lot of customers -> which design in SQL Server 2008R2 should be chosen [closed]

I have a task and I don't know how solve it :) So, we have a lot of customers who should use SQL Server for their applications. Design is standard and simply: Customer -> Remote Desktop -> ...
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808 views

SQL Server performance for tables having large number of columns [closed]

I have a requirement where I need to create a table with about 600 columns. Out of 600 columns about 200 columns will be XML columns. Other column will be of other datatypes such as int, varchar, ...
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1answer
206 views

Precautions when designing database schema if tables are going to have billons of rows

I am about to start work on telephone dictionary kind of project. Its confirm that there are going to be billions of records in dictionary table, and each entry from this dictionary table may have ...
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1answer
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Need for indexes on foreign keys

I'm struggling with indexes, primary keys and foreign keys... And the need of having them all. If I have two tables, both of them have an integer as a primary key. The first table references ...
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108 views

Datamodel design for multiple roles, country access

I am in the process of creating a data model for the below scenario there will be two hierarchies a) dept hierarchy (emp -> team -> dept -> branch) b) sales hierarchy (emp -> marketing manager -> ...
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1answer
170 views

Implementing foreign keys on generalized data model

Suppose the ASCII tree below is a UML generalized concept model. To represent these entities/classes in UML, lets assume [mammal] a super class, and the level 1 classes, [wild] and [domestic] are sub ...
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160 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 ...
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2answers
462 views

SQL Server 2012. Update second table based on input from first table

I have two tables in two databases: Table01 in Database01 and Table02 in Database02. Both tables have a column called UserID. The UserID column is created when the user creates a new account on the ...
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64 views

What is the “proper” way to design a database architecture when entry counts belogning to different users may vary wildly?

To give a context; we are going rewrite our application in Django framework. The database that is being used by the old system at the moment designed very poorly, without any respect to methodology of ...
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Database design to track inventory?

Would this be a good starting point for tracking inventory with several warehouses? If yes what is the best approach to sum quantity when displaying stock by warehouse/type/general? mysql structure ...
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avoiding unique key collisions across tables

This might be related to the idea of data warehousing, but i'm not sure, though it is extreme theory. We have a table where records get written to first, let's call it tbl_recording which looks like: ...
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63 views

is-a relation(ERM) to tables

i try to design a database with an is-a relation: Vehicles have some general attributes and the SubVehiclesX have some specialized Attributes. SubvehicleX is a Vehicle And a Person has a Vehicle ...
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83 views

How to check how the table structure effects the performance of my query

I want to check how the table structure of a certain table effects the performance of a delete query. This is not a generalised question, I have a table, with currently 2.2 million records ...
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2answers
235 views

How to establish a Two-to-One table relationship (PK-FK-CK)?

My question is about DB design and its principles. I am working on a Python application where objects are mapped to database tables. I have Projects and People objects, mapped to their respective ...
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231 views

Does my ERD account for my business logic

As part of my new and upcoming project, part of the business logic involves sending each and every one of my customers (assume they number in their 1000s) multiple (possibly customized) emails. Each ...
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113 views

Database design [closed]

I have tables college and department. In college, I have serial-number and college-names, In department, i have nos, college-names and department-name. My challenge is that having a repeated ...
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104 views

Method to keep track of large number of sets with high cardinality

We're building an analytics service. One of our needs is to maintain ~100MM sets each with anywhere between one member to 1MM members, with each member represented as a long. We need to be able to ...
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1answer
62 views

Accessing MySQL Database

I am designing a database for an application, which will be accessed by different front end programming languages, such as php, asp.net, android applications and iphone applications. I am confused, ...
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3answers
993 views

GUID stored in a varchar field

I have inherited several databases that use GUIDs as PKs. Instead of all the datatypes being uniqueidentifier most are varchar(50) and some varchar(100). Fields are true GUID some where created by ...
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Relation that combines entries with their subsequent entries, in order of date

I need to come up with a query that can do the following: I have a table with a bunch of transaction records, whose attributes are not important, other than the attribute Date. I need to come up ...
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1answer
77 views

Data modelling concepts

Let´s say I have 3 entities. Can I have them all linked to each other "forming a circle" where each one is linked to the other trough a many to many relationship. Cheers
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Can relationships have relationships?

I have the following requirements (as part of a larger system). In the database, I need to maintain a list of parts, suppliers who sell those parts. Many suppliers can sell the same part and each ...
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86 views

Table Design Cardinality

I am designing a database for an application, in that I need to consider both BUYER (BUYER_ID) and VENDOR (VENDOR_ID) as a USER (USER_ID). I have designed this logic in a following design. USER ...
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MySQL: What criteria should I base my table column order/arrangement/grouping on?

Does the order, arrangement or grouping of columns with large (such as long text descriptions) and small (such as bit and tinyint) field types have any noticeable impact on MySQL (InnoDB engine) ...
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1answer
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Is this table designed properly

I am trying to model the process of where one co-worker enters a statement of their proposed work procedure and another co-worker commenting and approving the statement. Currently I have one table as ...
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Foreign key constraint based on conditional column

I'm trying to figure out the best way to handle this situation: I have a table set up as follows: LEARNING CONTEXT ================ LearningContextID - INT - Surrogate Primary Key EntityID ...
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3answers
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Is it good practice to create new tables for new elements in a database?

I am trying to create a good model for a database that I need for an application. The way that I have tought about realizing it involves creating a new table for each new element that is added, but I ...
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Comparing 1 Database with Many Tables to Multiple Databases with Fewer Tables in Each

What are the pros and cons to creating one huge database with numerous tables or better separating the data into many databases that each have fewer, more relevant tables? Are there server ...
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1answer
171 views

Product quantity bound to colors and sizes table structures

I've been thinking about how I'll be able to create products with sizes and colors which will match the max quantity of a product (or their total will be the max.quantity ). Let's say I got a product ...
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1answer
150 views

If all variables are a subset of the candidate key, is the database design 5NF?

I have a table called LogMessages, which has the following columns: Level A numeric value which represents Trace, Debug, Info, Warning, Error or Fatal Time A UTC time Message Foreign key to a ...
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Table Design - User Management

I have designed a database design for a simple User Management System, this system consist of the following things, User - A user may be a Vendor / Employee / Buyer. User - A user may have more than ...
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210 views

Database design for holding read/unread content state

In forum application I have member table and post table. What I need is to keep track of what posts have been read by which members. What I thought about is to have a junction table with two columns: ...
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1answer
563 views

Add a column contains a photo

I installed PostgreSQL 9.1 under Ubuntu 12.10 And now I have a table called property I want to add a field that can be used to store photo(link to the photo or import a photo into a column?) But I ...
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How can I design a database that easily lets me recreate historical snapshots

I'm designing a database for an accounting system. In the system there are companies, and each company has many contracts. Each contract gives a company access to products, data types, or both. ...
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1answer
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Table Relationship cardinality

I am designing a database for my application, I got issue in implementing the following logic. A user may be a Vendor and also a Buyer. I have created a table for USER and created an another table ...
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1answer
97 views

Nullable One To Many w/Join Table - Indexing

I have a question regarding database design, I am working with PostgreSQL using Hibernate for ORM, the design I inherited includes the following tables users user_id (pk) user_name user_dob ... ...
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4answers
312 views

SQL Server: Database integration and synchronization

I have n SQL Server databases with the same data schema. On the other hand i have a web application that needs to retrieve, for some entities, the union of the information stored into the n ...
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How to manage primary key while updating [closed]

In the following table primaryKeyColumn is primary key. To maintain the data history I always uses the values with WHERE condition(WHERE StatusColumn=1) And will set the StatusColumn to 0 if the data ...
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3answers
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Are 2+ Foreign Keys a Bad Idea in any Association / Junction table?

(First time poster, very very long time lurker. I cannot find an answer to this question anywhere, so I now come out from the shadows to ask the experts). Is a junction table with say 4 foreign keys ...