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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master-slave vs masterless architecture

As per Riak's doc "Most relational databases leverage a master/slave architecture to replicate data. ... Conversely, Riak uses a masterless system with no single point of failure, meaning any node ...
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How do I define a 'flexible' relationship in my table?

I'm working on a large application, with tons of tables and a huge codebase. It's a system in which people have rights to use functionality X and/or functionality Y and/or functionality Z. ...
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Use ID from another mysql database?

I have a mysql database for form submission (written in PHP) data and a mysql database for CRM (using X2CRM) on the same server. When a form is submitted on my website the POSTed data of the form ...
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18 views

Trigger function check if all NEW.* fields exist in another table

In PostgreSQL I need to code a trigger function that checks if all the fields in NEW.* exist in another table that has the exact same name as the table that fired the trigger but appended with "_hv". ...
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124 views

Fetch data from database from multiple tables matching condition

I want to fetch data from the database. I have three tables in my database like listing_master_residential and listing_master_condo and listing_master_commercial. There are three tables and there is ...
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Help in Designing a CBT database

Please i need help in modifying or remaking the database so that i can mark answers to questions immediately. The problem is some courses have 50 questions, while others have 100. How can i design ...
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1answer
20 views

document and edges in orientdb

I was playing around with OrientDB lately and was create some classes and edges. I was able to create edges between documents, is this something that is expected from OrientDB when edges are ...
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11 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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17 views

What will be the Better database design for following table?

I am designing database schema for bulk mail system. campaign table is used to store the campaign details. Table Campaign ...
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44 views

Normalization for three somehow identical tables

These three tables are nearly identical. But, there are some exceptions. But, I can't find best normalized structure. Could you please help me? Here is the informations must be hold in database: ...
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1k views

Table Design - User Management

I have designed a database design for a simple User Management System, this system consist of the following things, User - A user may be a Vendor / Employee / Buyer. User - A user may have more than ...
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789 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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2k views

Ready-to-Use Database models example

Where can I find ready-to-use database models ? I don't need a database with data in it, but only schemas (UML diagrams). Perhaps something like the data models at this link, but much more complex ...
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898 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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38 views

How to save the design of an Access database — not the content — as text?

How can I save the entire design or specifications of an Access 2007 database -- not the data content -- as text? I have fallen foul of the "Enter Parameter Value" bug whereby a query pop-up shows an ...
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1answer
13 views

GROUP BY parentId and MAX childId

My tables are below: crm_conversions crm_messages_of_conversions crm_receivers_of_messages I want to get all of conversions of an user with only last message. I'm trying to get with the query: ...
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2answers
1k views

Will table inheritance in PostgreSql suit this situation?

Let's start off by saying, I'm new to PSQL and coming from a MSSQL background. I'm starting to design a DB in PSQL. So my main aim is to have a Main schema in this DB, which I am going to use to ...
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Access 2010 Forms not seeing imported data

I created a form that has several sub-forms. During testing with sample data everything works great. I can switch between sub-forms and all the data is correct. I deleted the sample data and imported ...
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how to enable powerdesigner 16.5 auto increment primary key for MySQL database

I am using powerdesigner 16.5 to model my MySQL database. Anybody knows how to enable its auto-increment primary key feature?
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107 views

How to model when you could have many (thousands of) attributes to a table (product)?

We have a main table, let's say, Product. It has several general attributes like 'Product Name', Manufacturer ID, etc. As of now, all these attributes are implemented in the data model as columns to ...
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how to resolve this insurance company database

Company offers 3 types of personal motor insurance to vehicle owners. It includes the third party insurance, fire and theft, and comprehensive cover. All vehicle owners need to purchase a motor ...
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1answer
10 views

Store data of feedback form

I am a novice at database management and doing a small project on Feedback System. My question is that I want to know that how i should store the data of feedback form. Suppose i have different ...
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3answers
122 views

Text Storage and Database Design Optimization in a SQL Server Database

Given a database with a number of columns (c), where some of these columns contain text that is one of multiple values due to a set CONSTRAINT on the columns, what is the most efficient way to ...
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1answer
65 views

Most efficient way to set up a database handling millions of links?

I'm looking at making a site that will potentially have up to a million users, and each user will have hundreds/thousands of links connected to a set of sites, as well as other info. I'm using mysql ...
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1answer
550 views

How to normalize my db schema for a quiz application?

I am putting together a quiz application. (I'm calling each quiz a "challenge") I have a "challenge" table and a "challenge_question" table which is pretty straightforward. challenge table: id ...
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1answer
36 views

Maximum Partitioning PostgreSQL

I have 400,000 records I need to partition. The records will increase 100,000 per year and those new records might need to have 1000 new partitions added. Here are some of my concerns: How many ...
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2answers
64 views

How to enforce data consistency across one-to-one relationship in an inheritance hierarchy

Consider this design for a typical school database: Person: ----------------- FirstName LastName SocialSecurityNumber Phone Email Student: ----------------- Grade Teacher: ----------------- ...
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1answer
575 views

How to store several lists and their items

The app I'm working on revolves around projects. Each project can contain several lists, and each list is made up of several items. Each list relates to a single project. Is it better to have one ...
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1answer
238 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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2answers
42 views

Unique across tables

I have a table containing users. Each user has a primary email and a flag indicating if the user is deleted or not (we never hard-delete users). However, each user can also have additional emails. ...
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1answer
24 views

Automatic deduplication (normalization) of strings in MySQL

The question is whether MySQL can use separate physical storage for strings transparently, but with the same operations that are applicable to varchar, including %. I have a large number of ...
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Finding missing_index_details in MySQL

MS SQL Server apparently can tell you what indexes would be useful for your query. Is there anything similar in MySQL? This article (scroll to "Find missing indexes") says that in Microsoft SQL ...
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1answer
159 views

Duplicate Relationships in Rails/MySQL Healthcare Application

Overview of the Application I am building a Ruby on Rails application to organize medications, using MySQL. The goal of this application is to provide dosage specific treatment recommendations, and ...
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1answer
380 views

How to design a database for financial bond prices?

I have following flat file table composed of bond deal names and asociated prices. Each deal name is identified by its unique CUSIP and ISIN codes and each deal name is classified with a certain ...
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1answer
43 views

Does MySQL exectution plan depend on available indexes?

Does MySQL choose an execution plan for a given query taking into account what indexes are available, or does it first choose an execution plan and then uses indexes if they are available? ...
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Relationships for database tables in HR/Compliance Database using MS Access

I am designing a dual HR and Compliance Database and am stuck on how to relate 3 specific tables. I have an Incidents table that tracks incidents, a Review table that shows data collected from reviews ...
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175 views

Need Help maintaining multiple databases for a multi-tenant application?

i need some information about multiple databases for a multi-tenant application ? I am working on a project in which we are maintaining separate database for every company? The Companies Database ...
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1answer
159 views

Handling a chat room in a database

I have been searching all day to find a better answer to my question but those I found was useful but do not critically analyse my question. I am building a chat room using php, mysql, jquery and ...
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1answer
220 views

Transpose MySQL rows as column names - DYNAMIC

My goal is to be able to calculate the time difference between the ticket timestamp being created and closed and if reopened Add time from being reopened to closed again etc.. I have an existing mySQL ...
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1answer
42 views

Is it possible to execute queries in random order?

I have a list of INSERTs, UPDATEs and DELETEs queries. My problem is that I always receive them in the wrong order (random), and I cannot know their original order. Are there techniques to ...
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1answer
24 views

Should my application utilize database credentials for user login?

I'm working on an application that has an ASP front end and a SQL Server database. The way credential management is currently performed is there is a custom built User Table in the database that ...
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37 views

Good way to harmonize data from different databases [closed]

I have three databases (an access database with user data in-house, a MySQL database of a data provider also with user data but stored in a slightly different structure (e.g. different field names or ...
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1answer
36 views

Why wouldn't I put the single preferred option into its own table, instead of having a 'Preferred' column?

In similar spirit to How to implement a 'default' flag that can only be set on a single row I would like to specify that, for any given list of possible names for a business, only one of the ...
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1answer
38 views

Database design - Projects with multiple Clients but only specific client contacts

I am in the process of setting up a database that among other things will track projects, clients, contacts. I am however stuck on how to design one piece of relationship. The part of the database ...
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2answers
18 views

ERD Design for Campground and Campsite

I am designing erd for campground and campsite. In general, a campground has many campsites in it. that lead to one to many relationships. but sometimes campsite has no campground, it appears as the ...
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1answer
26 views

EAV table question

What's the best design for taxonomies in EAV tables? taxonomy id autoincrement name unique terms id autoincrement tax_id references taxonomy(id) name text unique value text ...
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1answer
205 views

Building a branched versioning model for relational databases

I am database designer and at my current project I'm implementing versioning capabilities required to concurrently edit rows of data in RDBMS. The project requirements says, that data editing sessions ...
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3answers
680 views

Is a 5+ column primary key bad for large (100 million+) table?

I was reading about some real life DB issues, and one project had a 100 million row plus table that had 5 columns as its primary. I'm thinking this is bad, but can anyone tell me exactly why? EDIT: ...
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1answer
38 views

Best away to keep monthly records of loans

I'm trying to make a database to keep records of the amounts payed on a loan on a monthly basis. I already have tables for the clients, accounts, products and loans: create table product( id ...
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1answer
33 views

Should I have a parent table with only one field?

My database has multiple tables that all rely on dates. I was wondering if it would be smarter for me to take the date attribute and throw it in a parent table, rather than give each table a date ...