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

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Recipe Health risk Database ERD structure

I have these tables: First table(Recipe table), Recipe recipeid(PK,AI) recipename ingredients Second table(Ingredients table), Ingredients ingredientid(PK,AI) ...
3
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2answers
57 views

Calulating savings between two schemes

I've normalized a single table to reduce the number of nullable columns from 3 down to 0. The idea was to save a little drive space but I'm seeing a 45% decrease in space needed to store the same ...
3
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2answers
64 views

Best design for a many:many relationship issue

We have three types of entity, each with their own table: table:A(a_id), table:B(b_id), table:C(c_id) Each of these entities can have any number of email addresses and linked Twitter accounts. ...
3
votes
1answer
77 views

Which items are table entities and which are fields?

I'm a mystery novelist with a series of three books that will end up at around 20 novels. I am having trouble getting the tables and fields sorted out. I want to be able to: create a list of all ...
3
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1answer
142 views

Sql schema design advice

This question contains no concrete programming question, i would only like to hear some ideas, on how it would be appropriate to design my database. So recently I started designing an application ...
3
votes
1answer
251 views

Mathematical method for spotting irregularity in numbers flow

I am trying to build an engine which is going to predict orders for items inside shop. Three main variables are: Time-dates (x-axe etc 1.1.2013,1.2.2013 etc I do calculation one per day) Available ...
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1answer
722 views

Learning to draw entity relational diagram

I am trying to learn entity relationship diagram, following question is the objective. Information consulting firm has number of offices with employees. The employees can move offices depend on the ...
3
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1answer
106 views

Constraint to one of the primary keys as foreign key

Table1: grid_col (col_id,f_id,f_value) (col_id,f_id) is primary key. Table2: grid (grid_id,col_id,text) (grid_id) is primary key. I want to have a constraint for grid that, col_id ...
3
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2answers
94 views

Which design to choose in this case?

I am designing a database for a video game. I have some data structures like {x, y, z, dimension} used across multiple tables. For instance : Table player_death id: int player_id: int death_x: int ...
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1answer
3k views

How to optimize multiple self-JOINs?

I'm looking for advice on either optimizing multiple self-joins, or a better table/DB design. One of the tables looks as follows (relevant cols only): CREATE TABLE IF NOT EXISTS CountryData ( ...
3
votes
1answer
137 views

How to share resources among accounts?

Using google doc, I am able to share my documents with others. I wonder how they implement it underlying in terms of DB design? The simplest way I imagine is to use a joining table which keeps a ...
3
votes
1answer
461 views

SSIS Design consideration with object variables

I have an SSIS package for SQL Server 2008 R2. In the package I am required to work with an Access database (one to many) and iterate through it running validation checks with the data. The validation ...
3
votes
3answers
776 views

How can I improve my table design for different types of an entity?

Consider an accounting system as an example. I have an Entity called Client. Client can be of different types, with different fields applicable to different types. I consider creating separate tables ...
3
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1answer
105 views

Does avg_query for PgBouncer include update and inserts?

Trying to tune our application and would like to know if the stats data that pgBouncer shows as avg_query, according to the PgBouncer docs on usage: avg_query Average query duration in ...
3
votes
2answers
7k views

Database design for an E-commerce website

I am new to database design. I am designing a database for an E-commerce website, there are a lot of products to be updated, but while designing for product specification table I do not understand ...
3
votes
1answer
307 views

How to avoid Repetition in the Database Design?

I have currently the following database structure, Retailers ----------------------------------------------------------------- ID Name XXX XXXX XXXX XXXX XXXX XXXX ...
3
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1answer
1k views

Payment methods conceptual and logical model

I need to create a conceptual and logical (normalized) models of parking house according to the requirements below. It looks to me as a very simple concept that doesn't need all tables to have ...
3
votes
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 ...
3
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1answer
129 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) ...
3
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3answers
3k views

Empty LONGTEXT or NULL?

In my MySQL DB I have one field called html_contents that contains all the html to be shown in a webpage. Obviously the html could be huge, and certaintly bigger than 64KB, therefore I decided to use ...
3
votes
1answer
627 views

Applying user-defined fields to arbitrary entities

Currently we have an old (rather crude) system that has user-defined fields, which are mapped against rows in arbitrary tables. This was an after-the-fact modification based on a customer request, and ...
3
votes
1answer
264 views

Economic Database Architecture Possibilities w/ Data of Varying Length

I'm in the process of designing a MySQL database (InnoDB) that holds a large amount of economic data which our application scores. The size of the economic data varies a great deal: some measures, ...
3
votes
1answer
586 views

Curious Database building Problem (ER Diagram)

I am trying to build an EER Model for a Autostore that has 5 locations and offers a range of auto products. They offer car repairs and roadworthy tests as a service also. I need to be able to make ...
3
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1answer
96 views

linking databases for reporting

I am attempting to design a simple reporting feature for some financial market data. I have a few sets of data, and I am trying to figure out what will be the best way to organize the tables, in ...
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3answers
462 views

An “unlimited” data model

I need to store an unknown amount of fields. Some are numbers (like IDs, zip codes and times), some are short strings (like names and states), and some are longer strings (such as descriptions). All ...
3
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2answers
63 views

Should I put followers_no & following_no & product_no & last_login and etc in the user table? Won't updates cause fragmentation on the table?

I have a table for users in a social networking site. I want it to be efficient from ground up. If I put mentioned fields on the table then I have to update user's table on each changes. Should I have ...
3
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1answer
239 views

Database Relationships overview appreciated

I am helping to create a database via salesforce for storing information about Non-profit organizations. It has primarily 4 entities in the schema: Agency, Program, Project, and Contact, where Agency ...
3
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2answers
7k views

Tool for Reverse Engineering of PostgreSQL Database on Linux (Ubuntu) [closed]

Please suggest a tool to reverse engineer a PostgreSQL DB into an entity-relationship-diagram (ERD) or equivalent ?? Ideally, I'm looking for a simple ERD or UML class diagram in a format that is ...
3
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1answer
731 views

Do I have duplicate key indexes?

CREATE TABLE relations ( object_id BIGINT(20) NOT NULL PRIMARY KEY, object_term BIGINT(20) NOT NULL, UNIQUE KEY link(object_id, object_term), CONSTRAINT fk_term FOREIGN KEY(object_term) ...
3
votes
1answer
33 views

Store the content book in database, so that it would be updated afterwards or store them as document?

I have some books in (urdu) made with Urdu Inpage(tool for making pages in urdu) like this: problem that these document files are difficult to read in php because they gives unread-able characters, ...
3
votes
1answer
25 views

How to represent the optionality of a many-to-one mandatory relationship from the Parent to its two Child entity types in an ERD?

I have a Parent entity type with two Child entities, with a relationship cardinality of many-to-one (or M:1) from Parent to Child. The business rules say that: It is mandatory that the Parent ...
3
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0answers
39 views

Class-table inheritance without flag column

I am trying to implement proper Class Table Inheritance (aka Table Per Type Inheritance) in mySQL. AFAIK it's not offered out of the box so some hacking around is needed to make it tick. Current ...
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0answers
49 views

Ranking items on a per user basis

I have a MySQL DB with 20k-50k items and I want various users (let's say 1k-10k) to rank these items for themselves, so this is not going to be a global ranking but a per user one. All items are ...
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33 views

SQL Server storing predefined value sets along with open values

I have Cars with different Characteristics, Characteristics have values, which can be restricted by predefined set of values or be "open" values (any string). Characteristics and predefined values ...
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83 views

Best design to reference multiple tables from single column?

Proposed schema First and foremost, here is an example of my proposed schema to reference throughout my post: Clothes ---------- ClothesID (PK) INT NOT NULL Name VARCHAR(50) NOT NULL Color ...
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0answers
76 views

Is this user-storage database system efficient, effective and secure?

I am using: PHP Version 5.2.17-MIT-BACKPORT-GnuTLS SQLite 2.8.17 I have a database called users, which currently has a table called root. There will be others, once I get all the rows for root ...
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0answers
73 views

How to relate a [ parent common] table with (possibly many) subtype tables?

I am having a bit of a brain freeze. I have a table whose properties are the root of 4 distinct elements, for example: I need to relate SystemType to a SystemCommon, where one SystemCommon can have ...
3
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1answer
49 views

What process would you use to determine references on a database that has no integrity?

Imagine you inherit a database which has a bunch of tables, no documentation and zero referential integrity. Now you're trying to find out what are the various relationships between different tables. ...
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0answers
53 views

Is this ER Diagram correct?

Requirements: • Each customer has a name, a permanent address, and a social security number. • Each customer can have multiple phone numbers, and the same phone number may be shared by multiple ...
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0answers
37 views

why some one will use approximate data types for sales

I was messing around with Kartris online shop and I was reading this definition for a product version(you have basic information of a product in one table and many versions of products wich can have ...
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91 views

transaction replication causing too many deadlocks after adding a indexed view - what to monitor in order to avoid this?

I have created the following indexed view and its clustered index: This view was created on a subscriber database and all the tables used in the view are constantly being written to through the ...
3
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0answers
199 views

Form builder schema for SQL database?

There are many ways one can envision the solution, from the top of my head: Two table approach: Field table with (name, field_name, type, description, meta) attributes Form table with (name, ...
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0answers
81 views

One table or four?

I have four entities: Absence { ID, StartDate, EndDate, Days, Hours, Reason } Overtime { ID, Reason, Date (Integer), Hours (Integer) } Time in lieu { ID, Reason, Date, Hours } Holiday { ID, ...
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0answers
25 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? ...
3
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0answers
34 views

View of structurally same tables [closed]

Let's say I have two schemas (HR and Finance for example), in each schema I have a table with information about document types this department works with. Tables have the same structure: HR.doc_type ...
3
votes
1answer
57 views

Schema for scarce goods

I have following objects: (Rooms) which are (available in a certain period of time [in days]). During the time of availability they can be (booked) by (users). There are basically these four tables. I ...
3
votes
1answer
146 views

Modeling discounts - Product specific and Customer specific discounts

I have a reasonably simple database but have the following problem: I'm modeling a store + a lot of non-relevant stuff database. I have the following problem. I want to allow for specific products to ...
3
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3answers
3k views

How to store mp3 files in MySQL database using phpMyAdmin? [duplicate]

I am new to databases, but I want a database for my site to store mp3 files in it, so later I play them on my site by using jplayer. They say there are two ways to store data (in this case mp3 ...
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0answers
615 views

How to represent directed graph with multiple parents?

http://dirtsimple.org/2010/11/simplest-way-to-do-tree-based-queries.html provides an algorithm for inserting and deleting from a Closure Table. I'd like to model a similar data structure, except that ...
3
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0answers
48 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 ...