The logical model and/or physical design of a database.

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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 ...
4
votes
3answers
597 views

Should I use MongoDB or a NoSQL solution at all for this?

I apologize if this belongs in web applications or something. I'm creating a web application that is sort of a similar concept to github. Basically I plan to allow someone to create a design of ...
9
votes
2answers
2k views

How does using separate schemas affect SQL Server 2008 performance?

I want to use separate schemas for objects with different purposes in our SQL Server 2008 database. Right now we use a fairly mind-numbing naming convention to indicate the purpose of a table or ...
8
votes
4answers
356 views

Is this a standard way to design a database?

I recently learned about how relationships are defined in the database at work, and was wondering if this is a standard practice. Let's say we have two processes: Process A, and Process B. Process B ...
5
votes
1answer
449 views

Design for file based with many events

I'm not a database guy but I need to design a database to store events for our application. Our client app connects to remote hardware and syncs count data. The count data are csv files split into ...
1
vote
2answers
879 views

Designing a database tables for the following scenario

I just got following entities Employee, Client and Company. Where Employee and Client have one to many relationship with Company ie A single employee may be mapped to attend to many companies and ...
4
votes
1answer
2k views

Single database schema or multiple schemas?

I'm designing a website for an annual event. The events are similar but mostly independent year-to-year. I see 2 possible designs: A single schema with most tables having an EventID column to tag ...
26
votes
3answers
3k views

Should every table have a single-field surrogate/artificial primary key?

I understand one benefit of surrogate/artificial keys in general - they do not change and that can be very convenient. This is true whether they are single or multiple field - as long as they are ...
5
votes
1answer
986 views

How to handle “reference tables” in CouchDB?

What's the best way to handle "reference tables", tables that contain static data, for example a list with various kinds of ingredients for food? Multiple documents, one for each ingredient One ...
1
vote
1answer
137 views

Document Design and Document IDs

I was wondering about specifying id's in CouchDB. For example: House - Rooms -- Kitchen -- Living room -- ... - Windows - Doors There are some documents, like "House", where there is and will only ...
1
vote
1answer
74 views

Is storing values of a unique field shared between many web forms bad practice?

I am curious if it is considered a bad practice to use a unique table to store values asigned to a unique field that is shared between several webforms. The site with webforms will carry thousands or ...
5
votes
8answers
3k views

Should you ever not assign an unique ID to each row in a table? [duplicate]

Possible Duplicate: Should every table have a single-field surrogate/artificial primary key? I can't imagine ever not using a unique ID with every table, which is why I'm asking this ...
1
vote
1answer
118 views

How should I model this data?

I have a need to model the following requirement for a web application (PHP/MySQL5): A user can compete in a distance-based challenge which consists of entering progress along a defined ...
4
votes
2answers
2k views

Database design for dynamic Meta fields of an entity that shall be queried intensively

I'm designing a database structure for a system at which an entity can have a dynamic set of user-defined meta attributes. The meta fields (e.g.: popularity, conversion etc.) and skill values (int, ...
0
votes
1answer
4k views

SQL keyword difference between MySQL and Oracle 10g?

Good afternoon, Are there differences between Oracle 10g and MySQL with the CREATE, ALTER, DROP, REF, PRIMARY KEY, FOREGIN KEY and attribute variable type keywords? The reason I ask, is I'm planning ...
2
votes
1answer
299 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 ...
0
votes
1answer
254 views

How do I correctly design this database?

I am not a database designer by any means. I am a desktop programmer, but I am currently looking at implementing a website idea which will need a (possibly very large) back-end database. In my site ...
4
votes
4answers
2k views

How can I generate an Entity-Relationship diagram and SQL DDL from natural language text?

Good morning, Using LaTeX or another text-macro tool/library, how can I use natural language text to describe relationships, then generate an Entity-Relationship Diagram and generate SQL DDL to ...
1
vote
1answer
6k views

Set permissions on all objects for SQL users

I have a procedure that loops through all objects in the database and assigns them proper permissions to that object. I want to know if there is a better way to do this? I use a model database to ...
0
votes
4answers
903 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 -------- ...
0
votes
1answer
477 views

Depicting permissions to access table via E -R diagram

I am designing a database schema for a web application. Its a first time I am designing a database with a commercial aim. I have started with drawing E-R diagrams after going through requirements ...
22
votes
4answers
17k views

How to design a database for storing a sorted list?

I am looking to store a sorted list inside a database. I want to perform the following operations efficiently. Insert(x) - Insert record x into the table Delete(x) - Delete record x from the table ...
5
votes
1answer
10k views

How to get the foreign and primary key details for a table in SQL Server 2008

I would like to use 2 queries, one that lists all the foreign keys for a given table with the following information Schema name, foreign table name and the other that lists all the primary keys. Is ...
2
votes
2answers
366 views

Database Transfer from PostgreSQL to MySQL

Is there any method to tranfer the data and schema from a postgresql database to mysql?
6
votes
1answer
778 views

What makes an OLTP database an OLTP database?

This is a pretty broad question. I know the definition of OLTP. But it seems like unless you have an environment that has a clear distinction between OLTP and OLAP, in the sense of a database that ...
33
votes
7answers
20k views

Writing a simple bank schema: How should I keep my balances in sync with their transaction history?

I am writing the schema for a simple bank database. Here are the basic specifications: The database will store transactions against a user and currency. Every user has one balance per currency, so ...
2
votes
2answers
339 views

Indexing of Data Warehouse tables?

Maybe I have misunderstood something but I can recall reading an article which said that there is no reason to create non-clustered indexes on very large data warehousing tables? That is because ...
16
votes
2answers
10k views

How do I map an IS-A relationship into a database?

Consider the following: entity User { autoincrement uid; string(20) name; int privilegeLevel; } entity DirectLoginUser { inherits User; string(20) username; string(16) ...
3
votes
2answers
328 views

Data Model For Summarizing Student Info

I work for a school district and one of the many things the admin wants to know is how many tardies a student has for a given time frame. I could certainly go retrieve the count from the attendance ...
18
votes
3answers
9k views

Is nested view a good database design?

I have read somewhere long time ago. The book states that we should not allow to having a nested view in SQL Server. I am not sure the reason why we can't do that or I might remember incorrect ...
5
votes
1answer
969 views

In MongoDB, is having lots of small collections better than having one huge collection?

Huge collections have huge indexes that may not fit into RAM. Is that problem entirely solved with sharding ? If I have lots of small collections with small indexes, what are the options for storing ...
0
votes
2answers
2k views

What will be the best data model for membership based websites?

I am building a paid membership based website where user can signup for different kind of membership. Membership will essentially enable or disable certain pieces of functionality in the website. A ...
31
votes
5answers
6k views

Why is there still a varchar data type?

Many of my databases have fields defined as varchars. This hasn't been much of problem since I live and work in America (where the only language that exists is "American". ahem) After working with ...
70
votes
7answers
16k views

Why shouldn't we allow NULLs?

I remember reading this one article about database design and I also remember it said you should have field properties of NOT NULL. I don't remember why this was the case though. All I can seem to ...
2
votes
1answer
99 views

How to make a duplicate field cheap?

There are two tables associated with each one to many in a field. In Table 2, there are fields that duplicate the value in Table 1. Is there a cheaper way to ensure (guarantee) the correspondence ...
6
votes
4answers
236 views

Dynamic contacts database

I'm trying to create a database for contacts. I must have many categories for every contact, like Home, Office, Emails, Phones. In every category one can add more than one value. Also the categories ...
2
votes
1answer
781 views

Trusted Constraints and NOT FOR REPLICATION

Version and Build: SQL Server 2005 SP4 (9.0.5000) As a disclaimer of sorts, I am asking this question to generate some discussion and/or debate on the topic. I don't know if there is really a ...
3
votes
4answers
166 views

How implement a cancel attribute in a table?

Which is the best way to implement a canceled attribute in a database table, provided that less than say 3 % of the rows are canceled. For canceled data I want to store the additional information ...
3
votes
1answer
141 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 ...
14
votes
7answers
11k views

How do I force one record to have a true value for a boolean column, and all others a false value?

I want to enforce that only one record in a table is considered the "default" value for other queries or views that might access that table. Basically, I want to guarantee that this query will always ...
4
votes
3answers
385 views

Database Design Issues

My question consists of three parts: When can I be sure that my database design is perfect? Is returning to the database design to change some issues (i.e, adding new column, deleting a column, ...
14
votes
7answers
380 views

Which of these table designs is better for performance?

I have been asked to create something which tracks the daily cost to collect on accounts, and I am trying to figure out a database table schema that would support this. Here's what I know Company ...
12
votes
5answers
5k views

Do empty columns take up space in a table?

I have table that holds from very basic info. Just a title and a few date fields. There's one field called comments which is varchar(4000) Most of the time we leave it blank, but some times will enter ...
3
votes
1answer
743 views

Database Design: Storing Map Locations

When working on a game, I developed a database that used X/Y coordinates, roughly as: CREATE TABLE Map ( MapId INT IDENTITY PRIMARY KEY, X INT NOT NULL, Y INT NOT NULL, North INT ...
27
votes
5answers
27k views

When should you denormalize?

I think we are all familiar with database normalization. My question is: What are some guidelines that you use when you want to denormalize the tables?
6
votes
2answers
4k views

What exactly is a database engine?

I have gone through the definition on http://en.wikipedia.org/wiki/Database_engine several times: A database engine (or "storage engine") is the underlying software component that a database ...
5
votes
2answers
633 views

Table contains multiple names for same company

I have a table of monetary transactions that has a field for who the money was paid to or received from. Transactions are recorded using info from paper invoices, paper reciepts, internet reciepts, ...
26
votes
1answer
8k views

Designing a platform: one database or multiple databases?

We are building a web platform that incorporates multiple services, each with its own underlying data. These services are being built independently following the principles of Service-Oriented ...
2
votes
1answer
292 views

Where to save user data?

I hope this is the right stackexchange place to ask. Im really new using databases and I have a little question: Where to save the user data? I mean, if Im logged as "Foxandxss" on my app, and I want ...
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 ...