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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488 views

Help with Vehicle Service database

I am using the Desktop Vehicle Maintenance template in access, but i am trying to cater it towards our farms needs. We will be keeping track of the service's done on Trucks, Tractors, Equipment, etc. ...
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1answer
70 views

Creating a schema for various sizes of varchar

I am redesigning a database schema for an application I am working on, and one of the major changes I am adding is the ability to dynamicly add new "fields" into a form based administration area. ...
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1answer
2k views

Default values in SQLite3

When I created the table structure of my SQLite database, I provided a DEFAULT value which is used when no value is provided by the user. Now, because the application code changed, I need to modify ...
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1answer
776 views

How to translate high level entity relationship into schema

According to the following articles written by Dr. Chan, we can describe high level entity relationship. (see page-10,11 of doc-A and page9 of doc-B) •doc-A) English Sentence Structure and ...
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2answers
178 views

A Huge Database: Picking the right schema and data model

We want to store some genomic variant data but there are some problems, more important ones like problem of the data's immense size and variability. 1) Variant data can be huge. For example, a single ...
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1answer
822 views

How to design database for tree view with an infinite depth

I am trying to combine C# and SQL2005 for an application which need to have tree view control. One of user requests is to that tree view can user friendly grow into infinite dept of child nodes. That ...
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2answers
1k views

Model a family tree database in Access 2007

I designed my database with the intention of implementing it with MySQL, but have now decided to implement it in Access 2007 using form and subforms. While creating my UML diagram, I realised I have ...
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1answer
4k views

Concept to keep track of changes in all tables

In my current project I use about 10 MySQL tables (Doctrine as DBAL). I'd like to keep track of all changes in the databases (insertions, updates and deletions). At the moment there are two ...
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1answer
1k views

How to create a train schedule in SQLite3?

I am interested in what a SQLite3 database schema would look like for a train timetable. Generally this is presented in table format as the final result. Sample Schedule for M to F STATION A ...
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1answer
156 views

Entity relationship many to many

Is an association class in UML the same as an Link entity in ERD?
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1answer
853 views

Table structure/schema for spreadsheet-like web app (ex: Google Docs)?

I'm a front-end developer/designer who is trying to branch out and learn more about the back-end world. I've chosen Python, Django, and Postgres as my starting place. My goal is to build a personal ...
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1answer
196 views

Is dimensional modelling useful for modelling tables of calculations?

I have a set of tables that look a bit like this: Key 1 | Key 2 | Key 3 | Var 1 | Var 2 | Var 3 | ... | Var 200 ------------------------------------------------------------- X | Y | Z | ...
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1answer
11k views

Multiple left joins or subquery?

I'm working on joining multiple tables together to extract some data related to user "runs", this includes basics like runID, username etc but also joins to the run times and favourites. I have the ...
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1answer
411 views

Multiple values in lookup fields

I know newer versions of MS Access allow multiple selections in lookup fields. For example, if I'm collecting information on my students, I can have a field called Race with lookup values that ...
2
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1answer
2k views

Automated UML2 Class Diagram generation from SQL?

How can I generate a class diagram from an SQL database or script? I'll add the functions and set whether the attributes are public, private or virtual once the initial diagram is generated. I've ...
2
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1answer
287 views

How to design relationships for variant data?

Help me define the table relationships for data with multiple structures. I need to track leads. Leads come from multiple sources. Each lead source has its own data structure. I need advice ...
2
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1answer
136 views

Does document “depth” affect CouchDB performance?

I have a project where it is very tempting to use a deeply nested collection of data. But how does that affect performance? Are there any reasons why I should avoid doing this? I'm talking about lists ...
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3answers
927 views

Priority Inbox Database Design

I was just wondering, what would be the table structure for a messaging system similar to Gmail's priority inbox? If you're unfamiliar with the system, it prioritises messages based on the type of ...
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2answers
2k views

Is it better to store calculated values or recalculate them on request? [duplicate]

Possible Duplicate: Storing vs calculating aggregate values At an old job, we had this database, it wasn't normalized rigth, some tables wheren't used anymore, it was patch after patch. In ...
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0answers
60 views

How do I provide a failsafe for retrieval of data from excel to SQL

So say there is a process in place for importing data from excel spreadsheet to SQL using SSIS. And there are two tables, one with new data and one with data from its previous run. I sometimes have ...
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49 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 ...
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0answers
11 views

Alternate in access database [migrated]

I want to check whether a row exists or not before inserting a new one in Access 2007. I have the following working query in SQL Server but I'm having trouble converting it to Access. update category ...
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0answers
34 views

How to implement search for world-wide Wikipedia/OSM places with alternative-names

I would like to implement a search-backend which returns a location-aware search results of all Wikipedia / OSM place names, while recognising place names in all languages. Thus, if you search for ...
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0answers
21 views

Is it a good way to use an auto increment integer field as the primary key? [duplicate]

In database design, is it a good way to use an auto-increment integer field as the primary key? For Example, I have a tenant table, tenant_id is unique. In this case, do I need a auto_increment key? ...
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31 views

Design Question - Stock and OnSale Table

Background : I'm designing a solution for a repair toy association. Since they have office - I'll use Access. Plot : Stock will store items - I choose this primary key (Item_Id,Record_date) ...
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39 views

Better performance to have nullable columns or an extra table? [duplicate]

There are many ways to get rid of nulls in tables, and I have heard of various reasons to get rid of them, but can anyone show me some real numbers as to how your database might perform differently ...
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39 views

How To Manage Random Data Without Repitition?

We have a database design problem of a Learning System. Please can somebody help us ? These are the requirements : A person can register for a module which has "n" number of questions. The person ...
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58 views

How to store data where various subcategories have specific columns?

I'm new to database designing. I'll use MySQL and PHP. I'm designing a database in which I have a lot of categories and subcategories like given below: Product Table p_id p_title category_id ...
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1answer
31 views

Distinguishing Records with Related Fields

I'm a newer user (obviously) and would greatly appreciate question writing suggestions as well as answer suggestions: I have a lot of interrelated tables which largely depend on my Products table, ...
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1answer
124 views

Building a restaurant database

I am designing an Italian restaurant database, but I face some problems considering the database design, which lead me to a halt. The part that I find difficult developing is the dishes table. A main ...
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1answer
82 views

Best practice for when the ideal number of columns is unknown

I'm currently making a MySQL database to list products for an e-commerce site. Each product will have several sizes available which will each have their own dimensions and measurements (e.g. length, ...
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0answers
52 views

Database Design: Include Question Answer and Comment tables into Post table

I'm designing a database. This system has question, answer and comment. Question has some type of questions. In each type, there some differences so they're have some difference fields. Answer and ...
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87 views

Party Data Model / Universal Data Model Example

I am trying to implement Party Data Model / Universal Data Model in our application which needs to store different relationships between entities (People, Companies). Example of relationships: ...
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0answers
93 views

Storing phone number in E.164

TLDR; If I store a phone number in MySQL(or any DB with equivalent constraints), would the correct format be E.164 values into a VARCHAR(32) field? Have been reading up on format/storage of ...
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0answers
53 views

Improving performance of a weighted search query in SQLite3

For an intra-site search I have this table in an SQLite3 database, that relates ids to search terms with a certain weight: CREATE TABLE search_index ( id INTEGER(7) REFERENCES other_table, ...
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72 views

Why can't we have multiple cascade paths?

You can see that many questions have being asked about multiple cascade paths. For example: http://stackoverflow.com/questions/851625/foreign-key-constraint-may-cause-cycles-or-multiple-cascade-paths ...
2
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1answer
259 views

Rich text: VARCHAR, TEXT or BLOB in MySQL

Question: In my web application (php/MySQL) I will be saving rich text. This may be anything from a couple words to several pages length essay. I’m sure I could get away with using VARCHAR, TEXT or ...
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0answers
16 views

Filegroup design for Document Table for BLOB Storage

I have a table for storing documents as VARBINARY types in my database (I'm not using filestream). My database is setup with only one data file, but I am wondering if there is a benefit to creating a ...
2
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1answer
51 views

In SQL Server would misc pages be pushed out when an object grows within a mixed extent?

In SQL Server 2008-2012, objects (including tables) are first put in a mixed extent. An extent can accommodate up to 8 pages and accommodates more than one type of page (meaning: pages from more than ...
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0answers
12 views

Counting daily distinct records [duplicate]

I have a table that looks like this in Google Big Query: custID InteractionDate Purchased? Sales 1 20150312 F 0 1 20150312 T 200 1 ...
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0answers
103 views

Covering Index - Insert Performance

We are running some performance tuning on our database in SQL Server. The database in itself is pretty small with around 13 tables. But there are multi-level relationships between tables. When I try ...
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0answers
81 views

Storing URLs in a database

I am thinking about storing URL's in my database, but I am not sure whether the way I use is an efficient way to do things or not. Table name : url url_id (Primary Key & Auto Increment) url_value ...
2
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2answers
70 views

Should running number be separated column from primary key in database?

I have questions that blogged my mind on separating member number and member id. Suppose that we have a database with member id primary key of Guid type. Then, normally, when we view the profile (on ...
2
votes
2answers
109 views

Field types database design best practice

I am creating a cms system where the user can create fields to use in the templates of the website. I want to create different types like 'string', 'html', 'integer' etc. The user must also have the ...
2
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0answers
68 views

With SSD's and in memory tables, does a snowflake schema become preferred over a star?

With SSD's being very fast (reducing the overhead of joins), while more expensive (increasing the cost of redundancy due to de-normalization), along-with a focus on in memory tables (again reducing ...
2
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2answers
882 views

Best practice design when expecting large data in a table

I have come across a way that kind of works for me, and was just wondering if it would have any side effects, or, if I'm just thinking about this the wrong way. I first had this idea when I was ...
2
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1answer
69 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 ...
2
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2answers
54 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 ...
2
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1answer
366 views

Database design for a table with both bulk insert and single row insert

I have to design a table where records will be inserted in two ways. Bulk insert from a batch process from a delimited text file between 2 - 3 million rows in a short burst. Later the same records ...
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38 views

How do I design a database for different sets of measurements on different subjects?

I'm conducting a research project that consists in sampling different physical quantities on about 30 buildings, most of them single-family houses. Some of those physical quantities will be common to ...