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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54 views

Create one-to-many to two fields in different table

I have a database where I am trying to figure out how to join a table that contains an object called ModelType. The calibration table contains two fields (EffModel and BkgModel) that are based on a ...
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1answer
89 views

Clustered composite key high fragmentation and fill factor

I've recently made a table to hold the language preferences of my users as follow: CREATE TABLE [dbo].[systemUserLangPreference]( [systemUserID] [int] NOT NULL, [langID] [int] NOT NULL, ...
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1answer
103 views

data warehouse design help

I'm struggling with the design phase for a data warehouse. It's not the traditional sales example you find on MSDN or all books etc. I've been tasked with creating an education data warehouse, that ...
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1answer
51 views

Is it Ok to have one table with two relations?

I have an event table that has two kinds of participants. Each event will have many participants of each type. Is it good form to have a separate table for each participant type, each related to the ...
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2answers
49 views

Relations between a imeid, sim chip, and account from a cellphone company?

I've never really had a cellphone (that I owned the account to...long story), but at work we have them, and we want to get a series of relations between accounts, devices (mifi's, tablets, ...
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1answer
19 views

Duplicate Data from two column

i have a table which has only two column one is pid(Photo ID) and another one is tid(Tag ID) +-------+---------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | ...
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30 views

Table join inheritance

I create db with Person, Client, Employee, Manager, Developer. I'm interested what is the best way to put the data in tables. In which cases should programmer unite Client in table hierarchy with ...
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1answer
105 views

What's better here - a single column or multicolumn primary key?

Let's assume you have a table groups and a table item. Each item belongs to exactly one group. It is an inherent part of that group. An item cannot exist outside of a group and it cannot be moved to ...
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0answers
25 views

Basic Design Question about one to many in a table

Sorry for the basic question but I am new to all of this! Say I have a table named Runs, and each table has Run: id (primary_key) data (String - path to a data file) status timestamp ... ...
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61 views

Modeling a db that has products: What are the good practices/solutions? How to treat grammar variations in the words?

The problem is: A Company belongs to a sector. A Company produces products. A Sector contains products. A Product belongs to sectors. Three entities: Company, Sector and Product. And it's a ...
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35 views

Is it possible (or good practice) to register data upon Deletion of a record? What would be a better solution?

The problem is the following. A company has one or more representatives (a person who speaks on behalf of the company). When a representative is deleted, it's desired to keep it in an list called ...
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134 views

postgresql bigserial or sequence using jpa

I'm a java developer working with jpa, before to define the indexes in my entities i would like to known which one is faster o better to use?.
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3answers
356 views

MySQL vs. Microsoft Access [closed]

I'm trying to aggregate about 500-1000 MS Excel files that deal with various small business issues (inventory, purchase orders, etc) and I'm currently trying to decide what kind of RDMS I should use. ...
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2answers
113 views

Implementing voting system like reddit/StackExchange?

In creating an application that would require a voting system similar to that of StackExchange or reddit, I want to know how the database tables should optimally be structured. So far, I have ...
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1answer
64 views

Database Over Normalized [closed]

How can you tell when a database is over normalized? Example: I have a database for employee. These are the following tables involved: User - contains email, password, companyId Profile - ...
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0answers
29 views

Organizing a couple tables in postgresql

I have a data structure that is represented like this: { 'question_id': 1, 'is_required': False, 'question_text': [ { 'id': 1, ...
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1answer
60 views

Does redundancy exists in this table?

I'm studying a DB course and I found this table: In this exercise, the objective is to determine whether the table has redundancy or not. According to the definition of redundancy Data ...
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1answer
35 views

Should I assimilate all address lines to a single line?

I'm new here, so I'll keep my question straight and short. I am building a webapp that lets users select some product, submit their details and place an order. Currently, my ORDER table contains only ...
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1answer
73 views

Database Normalization: A Case Of The NULLs [duplicate]

I'm trying to learn about proper database management and am having a hard time with designing a database that doesn't rely on NULLs. If you think I'm crazy for embarking on this, it is because of SQL ...
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27 views

Second opinion about elimination of possible redundant database column

We currently have a Widgets database table were we track the widgets the company produces. When a widget is produced the widget information is added to this table. This Widgets table contains a Status ...
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1answer
93 views

Database Design for NoSQL Fantasy Baseball League

I am trying to create a proper schema to place scraped data into, using a MongoDB database. Currently it looks like Team { id : id, name : String, teamLink : String, username : ...
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3answers
57 views

Should this be a foreign key? [closed]

I'm working on a school project and I need some help. I want to create three tables which should contain these fields: User UserID (AI, PK), UserEmail, UserPassword WorkGroupMember GroupID(PK, FK ...
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0answers
19 views

Problem in altering PK columns with macro

In Embarcadero ER Studio Data Architect (version 9.5), I have a problem in a macro i am realizing to import the contents of two excel files. Basically one of them contains informations about ...
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1answer
237 views

Database design for eCommerce website with multiple products having huge specifications index

I am designing a web site for online shopping and I have a question related to that. As you know that shopping website may have different product with different statistic/specification. What is the ...
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70 views

How to increase application performance with Centralised SQL Server [closed]

I’m trying to get my head around to make better way to increase the performance of my application System based on single SQL Server with 50 clients tablets pc(its connected to local wireless). my ...
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5answers
1k views

Is it impossible to store 2^266 records on a database of some kind? [closed]

Each records weighs 52 bytes, is it possible in today's technology if someone had the storage needed? What kind of db would hold the data and will make it possible to retrieve it. An example record: ...
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48 views

Reduce read write delays in specific database setup

I have a database with a large table with 15 columns (type double). It contains a large amount of data (~ 100 rows of data for every second. Holds 3 days of data). I also have a real-time program that ...
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1answer
67 views

Confused on how a value gets added with the DEFAULT constraint

A recent definition I've read about Default Constraints: DEFAULT is specified for a column to assign a column a specific value if no value is specified when a row is added. I believe I've seen code ...
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46 views

Efficient way to fetch/update X records in a loop

What I need is a simple process that handles requests. I have setup a simple table as follows: CREATE TABLE Requests ( id INT NOT NULL AUTO_INCREMENT PRIMARY KEY, request_param VARCHAR(250) ...
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16 views

Performance One Row With Total Vs Multiple Rows with Seperate Values?

Not 100% sure how to explain this situation but here it goes: I am building an Inventory Database that all items received are entered into and a label is created for each Container, that is going to ...
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34 views

Need help with data model

Schema does not list all fields, but only the relevant ones User adds credits/funds to his account using paypal or Internet Banking (which has to be verified manually, and approved, so the 'status' ...
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2answers
99 views

How to make a better Data model

I am creating a database system using MySQL for a group in my school (a University). I am new to MySQL and its usage.I have started with the data modelling process, since this process will be the main ...
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1answer
57 views

3 way junction table and redundant value

I was constructing a conceptual design for database in relational model until I stumbled upon some issue. My progress so far is: Asset Type Table +---------------+-----------------+ | asset_type_id ...
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6answers
373 views

Efficiently storing irregular/repeating intervals (think calendar/events)

I am developing a service that relies on users being able to recieve messages that they themselves choose. These messages need to be stored somewhere before they are send for processing. Right now ...
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1answer
76 views

understanding (and modelling) grocery shopping lists

I am having a hard time understanding how multiple product orders are mapped out. What is the best way of modelling a shopping list for multiple customers? I am developing an C# application that ...
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61 views

Alphanumeric field in MySQL

I need to create a character field with some rules, they are, Field name: contract_number. Rules: Contract Number Contract number must be alphanumeric. Contract number must be unique. Contract ...
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1answer
288 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 ...
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1answer
44 views

Fetching User Recent Status

I am running mysql with MyISAM storage engine to store user status(user updates data). To load user recent updates data i am using this query: $limit = 20; $uid = 3; SELECT * FROM userstatus WHERE ...
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1answer
59 views

Is this diagram possible or correct?

just starting to learn to design. I don't know the term in english to describe this type of design, so I'm here for some help. Can this "specialitzations" have a relation like this one? Thanks!
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1answer
30 views

Database engine that share a row among multiple tables

I'm wondering whether exists any database engine that can share cells or rows amongst many tables. For example: TABLE Customer ( CID: int Fullname: nvarchar(50) Age: int ) TABLE Group ( ...
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1answer
48 views

Attempting to identify transitive dependency

Hello I am attempting to identify a transitive dependency in the following diagram. I think that possibly the determinate of "Subtotal" is "Quantity" and "Price Charged" but I'm not sure if "subtotal" ...
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2answers
96 views

Confusion with Foreign Keys

I've been tasked to build a somewhat basic Prisoner database and I've run into a situation where I don't know what the appropriate route to take is. I have a Prisoner table, that looks like the ...
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1answer
37 views

Design for hierarchical embedded database

The goal is to construct a hierarchical database of Objects having the following format: TypeA -> ObjectA [values, contains ObjectB*, ObjectC*, etc.] TypeB -> ObjectB [values, contains ...
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4answers
99 views

T-SQL: Complete Database in one table

at a relational data model every logical relation is a single table with values and so on. I know someone who is this too much work and he wants to create only one table which contains all. This could ...
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1answer
35 views

How do I “link” two or more rows of the same table with a unique “link” id?

I am looking for a better way to create a link between two or more rows of the same table, but the link itself must have a unique ID. What I am currently doing seems rather convoluted. I have a ...
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0answers
191 views

Conceptual data model for a billing system

I am working on existing MySQL database, my task is to create a new data model for a billing system on that existing application, I have created a conceptual data model, as given below, My ...
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1answer
29 views

Database structure for product attributes on orders

I'm making a POS and currently kind of stuck on the order proccess due to the product attributes. As of now the DB looks something like this: tbl_products tbl_attributes (attr id, name, extra ...
22
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3answers
2k views

At what point does one database per client become unfeasible?

For one of our systems, we have sensitive client data and store each client's data in a separate database. We have about 10-15 clients for that system. However, we're developing a new system that ...
2
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1answer
35 views

How can I model and enforce constraints on a categorical item contained in a collection?

Scenario: There is a collection of items where each item belongs to 1 category. There is a collection of buckets which may contain at most 1 item from each category. Oh, and an item may belong to at ...
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1answer
52 views

Single MySQL DB contains both push and pull data. Recommended path to replication?

We have a single deployed (MySQL) database that contains both user tables and product tables (currently in the same DB). The product tables are "pushed to production" data -- they are generated in ...