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

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The four properties of a primary key

In our dbms class, these were the four properties of a primary key discussed for Oracle. Unique Not NULL Fully functional dependency Indexed I understand all the properties except the 3rd one (...
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2answers
516 views

What is the best database design to keep track of fields with multiple values?

I am trying to dynamically build a form with a label (field) and a user entered value (fieldValue) but the form can have several different control, like a combobox, textbox, listbox, checkbox, etc.... ...
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1answer
2k views

Many To Many Relationships

I am working on a conceptual model for a database. I have the following entities: Student (id, name, date of birth, department) Subject (id, name) This is a many-to-many relationship, one student ...
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3answers
11k views

Correct way to design a shopping cart websites database

I am in a web applications course. My instructor really didn't like the layout of my database, saying it was incorrect in pretty much every way. Fast forward 2 months when I'm remaking the website in ...
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2answers
4k views

Conversion of statements to E-R Diagram

EDIT: PLEASE DON'T CONSIDER ARROWS :) statements are "A teacher can teach many courses. A student can enrol in many courses. A course may be a part of one or many programmes. A teacher can be ...
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What is the difference between int(8) and int(5) in mysql? [duplicate]

I found out, that if you have a field defined as INT(8) without ZEROFILL it will behave exactly as INT(5) in both cases the maximum value is −2,147,483,648 to 2,147,483,647, from −(2^31) to 2^31 − 1 ...
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1answer
49 views

How to constrain data

I have 3 tables which are related and a constraint on one of them which I can enforce in software but I don't know how to enforce in the database. I have a series of providers who send a set of data. ...
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3answers
7k views

Software tool to visualize and print DB diagrams [closed]

I have some SQL Server databases and use SQL Server Management Studio to manage them. However, I find that is not very friendly to create, design and print database diagrams (for existing tables). ...
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2answers
6k views

SQL Server Database Diagram in SQL Management Studio creating multiple schemas

I'm using a multiple schema approach (Multi-Tenant arhitecture) in the same DB and it's working great. I can use EF bounded contexts and split domains appropriately. According to MSDN, multi-...
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2answers
210 views

Database setup/design for multiple services

I am working on a new MySQL database that will store orders/customer information for around 15 different services. 7 of the services are similar in regards to the information that is stored with a few ...
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1answer
69 views

Adding specific information to a local file

I have several files on a webserver (not stored in the database). I'd like to store several information to this specific file. The user should be able to post comments about this file. My question ...
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2answers
398 views

Database structure for a system with multisite

The system I'm working is structured as below. Given that I'm planning to use Joomla as the base. a(www.a.com),b(www.b.com),c(www.c.com) are search portals which allows user to to search for ...
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4answers
6k views

MySQL unique constraint across two columns

I have a table defining relationships Src smallint(5) unsigned NOT NULL, Dst smallint(5) unsigned NOT NULL, other fields I need to add a constraint that says if a given values is present in one of ...
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1answer
681 views

How should I model a worflow of status/activities ? (rules like “if is 3 go to 4, if is 4 go to 5” etc)

I'm trying to model a workflow (status and activities) to create "rules". Let me give you an example. The main "object" let's say are "vehicle requirements", I will have this table: idRequirement, ...
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1answer
142 views

Can I place the attribute in the Entity, when the foreign key is also already present?

I am using DBdesigner Fork for generating ER diagram. I have the 'Company' as an entity for which can I place the attribute of 'idShares', despite of having the foreign key of Shares Entity in the ...
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1answer
728 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 ...
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1answer
330 views

Application with “configurable” columns : how to model this

I'd like to do a status list. I have 1..n projects. Each project contains 0..n tasks, for which I'd like to report a status, next phase, priority, etc... For each project, I'd like to setup which kind ...
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6answers
5k views

using IDENTITY column with increment -1

I need to run a sql server logging db with 2 main tables in 2 seperate datacentres writing to both at the same time. I had the idea of restoring the db to the new datacentre and then reseeding the ...
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1answer
120 views

Advice for designing a complex/multipart application [closed]

I'm designing a software application for my medical carrier. It is very complicated, with many parts and many small details. Some experts advised me to divide it to parts, then design the database ...
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2answers
2k views

Database Design - One table for different types of transactions

Considering a procurement system as an example. Would it make sense to have one single table for the following: Quote, Order, Invoice and Credit Memo? There will be some details that are different. ...
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0answers
55 views

How to properly design this type of relationship [duplicate]

I am building a model with the following requirements: Items may have attributes Attributes may be of type: 'Choice', 'FreeText', 'Number' I am not quite sure how to relate the item to attribute ...
4
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1answer
238 views

250 billion rows - computing interconnectedness on a really huge scale

I have a table of approximately 700k rows, each identified by a unique itemnumber. Each row/item can be associated with any of the other rows/items in the table by calculating a single numerical ...
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2answers
124 views

Table Design - Identical tables for different statuses

I am developing a transactional System and the below is a simplified scenario of my problem. Users enter JOBS in a system. A User first enters a JOBS with a DRAFT status (and the Job is given a ...
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2answers
85 views

Referential Integrity - Re-using table

This is a simplified example of a design issue that I am facing: I have 3 tables: Car, Ship and Bicycle. I need to add an "activity logging" table that records user actions such as deletion and user ...
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1answer
52 views

Should I create a new table for store information of an associated object with object need to create

I'm not sure if topic can get you understand what I want to explain. Follow guide in my old question, now I have these tables and its columns: Course: name,... Topic: name, course_id Question: ...
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1answer
419 views

Modelling Hierarchical attributes

I am trying to figure out the data model for a retailer. The retailer has several stores across the country and they are modeled using the following hierarchy: Channel -> Zone -> City -> ...
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1answer
2k views

How to model entities in an entity relationship diagram?

I'm a beginner Database designer and wondering if anyone can help me understand this. Let's say we want to design a system that has, among other entities, an entity called Vehicle, and another one ...
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2answers
832 views

What happens to the index of a primary key after a DROP CONSTRAINT?

I am running PostgreSQL 9.1.4. I have a table with many existing rows, and a bunch of other tables with foreign keys pointing to it, for which I am trying to : 1 - Remove the pkey constraint on the ...
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1answer
136 views

which design better when use foreign key instead of a string to store a list of id [duplicate]

Possible Duplicate: Is using multiple foreign keys seperated by commas wrong, and if so, why? I'm building online examination system. I have designed to table, Question and GeneralExam. The ...
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2answers
1k views

Should I use SQL or NoSQL for this specific design (surveys)?

Building a small web application to create satisfaction surveys with a default list of questions and responses. The application is for a small audience of people (5,000 max) with surveys sent out when ...
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3answers
2k views

Are there any tools to go from ERD to DB design and vice versa? [closed]

I'm learning DB design and looking for some tools, preferably open source software, that could help go from an ERD to a DATABASE and vice versa. For the record, the database i'm using is MySQL.
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3answers
746 views

How to model a 1..1 Composition Relationship

We have a couple of entities/relationships of the following kind: Entity Event has a TimePoint The TimePoint contains time information about the event. It belongs to that event and cannot be used by ...
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2answers
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Select column names whose entries are not null

I would like to have a list of those columns of a table that have at least one not-NULL data entries in them. In other words, I would like to get the column names for which the following returns at ...
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1answer
582 views

mysql session logging tables

I've been building a session logging system for our sites. We get around ~15m hits a year and at the moment we're really only interested in stats about people who logon to our sites. Our table ...
5
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2answers
911 views

Introducing an 'age' category in a patients database

I want to do the following in my DB related to patients: when patient inserts his birthday it shows his age category as: infants, children, adult, elderly... etc. to help me classify my patients how ...
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1answer
106 views

Setup logical Database model for measurements

I'm struggling to set up a logical model for the following spreadsheet: (See a close-up of the table here.) My problem is that it is not clear to me how to deal with the "gap" values where each ...
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2answers
1k views

Keep total transaction in invoice application

I want to make an application called as Invoice Application with MySQL database. Now I have designed this database. Now I want to know is this database good for Invoice Application. I will use MySQL ...
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2answers
11k views

How to make a trigger that will compare input with a value of other table?

I had made two tables with the following fields: TABLE 1: "Bookings" FIELD: "fk_flight_number" FIELD: "date_of_reservation" TABLE 2: "Flights" FIELD: "flight_number" FIELD: "...
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3answers
561 views

Storing Phone Numbers - Proper design

First off, I'm not a DBA, I'm a software engineer and have been building applications which are database backed for my entire career. One of the things I remember (maybe incorrectly) is that when ...
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1answer
587 views

DB stored procedures: how do they help increase security in web systems?

The usage of Oracle PL/SQL procedures for controlling data access is often emphasized in PL/SQL books and other sources as being more secure approach. I'v seen several systems where all business logic ...
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3answers
8k views

Many-to-one Subselection in single query

I have two tables with a foreign key from T1->T2, in a one-to-many relationship. That is, 1 tuple in table T1 is associated with 0..N tuples in T2. To create a simple example, lets say T1 is Cars, ...
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90 views

what is the best choice from those two tables?

what is the best choice from those tables?? table A : keep DB simple with lower number of tables ... but i will find difficulties if i wanted to extract certain data from column of doses coz it's ...
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1answer
152 views

a question in tables relations

Table A is linked to Table B , and Table B is linked to Table C using primary and foreign keys My questions: Should i link Table A to Table C too?? Or Table B can act as intermediate link between ...
3
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1answer
132 views

Help to create indexes to improve query performance and reduce report generation time

The database in SQL Server 2008 has these tables below - the main table being the Master: Master A_ID (PK) SYSSerialNumber Bootlog SequenceNumber FileName Cfg Unique(serialnumber,sequencenumber) ...
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1answer
169 views

What MySQL storage engine and table schema should I use?

I am making a web project and I created necessary and the most important table, but I am not sure that I did it right. In this site users will post data like text, picture, text's category, etc. I ...
2
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2answers
457 views

Please review my first thought-out attempt at a database schema

I am researching database design and theory and have finally made a thoughtful attempt at creating a schema that would be based upon SQL. I would like, if someone has time, to review my layout and ...
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2answers
171 views

How to store massive quantities of machine generated data?

I am tasked with developing a system that stores massive quantities of machine generated data (syslogs) from a number of server farms and I am wondering what tools you fine folks use such instances. ...
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2answers
1k views

Save history editable data RDBMS

I want to make application like testing system. Every question has one or many variant of answers (and one or many can be right). I apologize that tutors and students use my testing system. It means ...
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1answer
314 views

Does my design adhere to 3NF?

I created this schema with OpenOffice. Does this design adhere to 3NF ? (A relationship link between Equipment and Supplier_Equipment , Customer and Membership should be created but OpenOffice ...
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2answers
79 views

How to Handle Database for Application which Starts from Scratch Annually

I am working on an application which will be used by an organisation annually, however each year they will be starting from a clean sheet. Which of the following two approaches (or any other approach) ...