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

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1answer
51 views

How can I better model the relationships in this project?

I'm developing an internal tool (as an intern). We deal with a lot of hardware, which is all custom and managers have a hard time knowing who is developing on what machine. The three main things to ...
1
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1answer
41 views

Data transferring

Is there any practices to transfer data from two databases that have different structure of table ? For example : old system : table [folder] with col: FolderId, name, age, sexe, date, orders New ...
6
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2answers
149 views

Creating relationships between tables that where not specified in the given UML diagram

Good evening! I'm working on designing my very first actual database from the following UML class diagram (in French unfortunately): I'm at the point of creating the relational sketch of it which ...
0
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0answers
65 views

Which NoSQL Database is best suited?

I have been reading a lot of blogs trying to determine which NoSQL database would be best. I am looking at moving from file based (xml) storage to using a database. The application will be storing ...
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0answers
29 views

Mongodb database design

I'm planning to implement this schema in Mongodb, I have been doing some readings about schema design, and the notion was whenever you structure your data like a relational database you must be doing ...
0
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0answers
53 views

Normalized college database desgin

I am trying to create a college course database. The College offers UG and PG courses in various departments. Departments include program streams like MCA, MBA, and Engineering. MCA courses may be ...
0
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1answer
59 views

Maximum number of TEXT/BLOB columns per table/performance of table with many of them?

I've created a system that generically imports CSVs into a database table with metadata columns for keeping track of when a CSV record has been changed, and it allows filtering on CSV columns instead ...
5
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2answers
283 views

Table Relationship - One to Few (Many)

I know the title may seem confusing but I have yet to find a solid answer to this design pattern. Let's say I want to create an Employee table and have multiple addresses for each employee. So this ...
2
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0answers
48 views

Looking for suggestions to model a database of Electrical Components

We have a database of electrical components and I am trying to make sure I have a good design. I am not a database designer (my comfort zone is designing with these hardware components), so I am ...
0
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1answer
64 views

Designing table for document annotation with future columns

I am working on a web application that allows students/researchers to annotate PDF documents shallowly by (manually) counting interesting phenomena. Right now, there is a total of about 45 of these ...
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0answers
25 views

Time Series on Postgresql

I am developing a software that have a dataset time series like this: id_equip, Timestamp, Double v1, ..., Double v30 The size estimate is 5.000.000 rows by year and the time of response is very ...
0
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1answer
41 views

Altering column data SQL [closed]

I have a set of car data, one of the columns represents the registration year. I want to change this column to age. As the data is from 2010 I assume that the following statement should calculate the ...
2
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1answer
80 views

Many to many between lots of tables?

TL;DR: How could I set up many-to-many relationship between that many tables and is it viable/recommended? Each body type has its own table Each car in each body type table can has several features ...
2
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1answer
72 views

Unique key based on many-to-many pivot table

I have to manage artists and albums tables: | artists | | albums | | album_artist | +--------------+ +--------------+ +--------------+ | id | | id | | id ...
0
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2answers
51 views

How can I create a join on three tables, each from a different database?

Here is a simplified example of what I'd like to do: SELECT a.create_time, b.create_time FROM DOB.dob_state AS a JOIN numID.numID_history AS b ON a.create_time = b.create_time; I'd like to join ...
1
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0answers
24 views

Database design for different, but related, objects

I'm new to relational databases having enjoyed the flexibility of nosql to date. I want to store data about 'estimates'. An estimate takes a set of parameters that depend on which product it is an ...
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1answer
110 views

compare file-based systems and a relational database [closed]

I don't know the exact difference of both can you please compare file-based systems and a relational database?
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1answer
31 views

Why does 3NF Normal form allow transitive dependency of prime attributes?

I'm just a beginner in Relational Design, When i came across the definitions of 3NF and BCNF. According to 3NF, Any non-trivial functional dependency X-> A shouldnt exist unless X is a super key or A ...
27
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20answers
2k views

How to dive into an ugly database?

I'm sure many of you are/were dealing with a ugly database. You know, that database that isn't normalized at all, that database where you have to do a large painfully query to get the most trivial ...
-1
votes
1answer
29 views

Multiple references to another table, but I don't know how many

I have two tables in a database, folowwing this model: scientists : id (int) | name (varchar) | surname (varchar) | publications (int) publications : id (int) | fulltext (varchar) I would like to ...
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0answers
15 views

Product Features table for No Sql Databse

I want to design database to save products features. Actually i want to store all features of mobile given on this link http://www.gsmarena.com/samsung_galaxy_j7-7185.php After search on google i ...
0
votes
1answer
35 views

DB Design - 1 column for each dataset OR dataset_name AND dataset_value?

I am creating a database table for storing numeric time-series data sets regarding cities that will be accessed via a web app. Primarily annual, quarterly and monthly data will be stored in it. ...
0
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0answers
26 views

Modeling a database with UML scheme and every type of relations

Good evening! This is my second database designing, the first one can be found here. I want to find the relational scheme of bridal registry database given in the following French UML graph: I ...
3
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2answers
56 views

Is it a good approach to duplicate data in a database?

I have a program that needs to store traceroutes (among other data). Here is a diagram that depicts the business scenario: My use case right now is to store the traceroutes using the following ...
3
votes
3answers
281 views

Normalising Customers and Employers with a people table

At what normalisation stage is it recommend to split say Customers and Employees into a People table and then link to the unique attributes of Customers and Employees? I can't seem to find the ...
1
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1answer
35 views

ON DELETE CASCADE doesn't work even storage table is InnoDb

I tear my hair with the ON DELETE CASCADE Clause. In fact I have two tables I'm on linux and I have installed lamp with phpmyadmin. That's the tables : CREATE TABLE a( Idatable bigint(20) ...
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0answers
18 views

SQLite text columns

When having a table in SQLite that has a TEXT data type, is there any implication if the length of the contained string differ significantly?
1
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0answers
29 views

problem with column oriented dbms features

I am currently looking for a free(or at least low cost) column oriented DBMS with really good compression abilities (at least 10:1 ratio) and fast response time. Having evaluated multiple open source ...
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0answers
17 views

Data Modelling of product and product variations

I want to model product and product variations using mongodb (mongoose) I am really confused with how shall I model both I need to add stock and price to variations. Variation can be of anything (not ...
1
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0answers
43 views

Ternary relationship with history tracking

I have the following entities Procedure -> id_procedure , desc_procedure . Status -> id_status , desc_status . Subprocess -> id_subprocess , desc_process . The rules are: 1 ...
1
vote
1answer
42 views

How to design a database for query builder project?

I have this project in which user can create queries using web based UI in which there will be list of columns and applicable operators. Later users can edit these queries, too. So I need to store ...
1
vote
1answer
48 views

Limit the number of records depends on the part of primary key

I created database for football matches. I have 2 tables with a many-to-many relationship, so I also created a junction table: Referee CREATE TABLE referee ( id_referee INT IDENTITY PRIMARY KEY, ...
3
votes
1answer
36 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, ...
11
votes
2answers
4k 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 ...
3
votes
1answer
42 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 ...
1
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0answers
17 views

Time series data and utc conversion

I'm storing data in minute, hour, day, month and year buckets. All data is stored in UTC. Let's assume a client is in PDT time (-07:00 UTC) If the client wants to query for the hour sum of 4/23/2016 ...
1
vote
1answer
62 views

Database design for ordering complex products

I'm working on a platform in which you can order food from different sellers. Currently the platform is working and restaurants can create food products while clients can order them. Easy enough. A ...
1
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0answers
21 views

Varchar PrimaryKey. Clustered or nonclustered? [duplicate]

I am working on a legacy database. The primary key is clustered varchar(128) and the table contains a high volume of data. Does it necessarily help performance if I change the clustered PK to ...
2
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0answers
47 views

Clustered index on a fact table

I'm trying to work out what field(s) to use for the clustered index of my fact tables (which all have a similar structure). I'll use FactSales as an example: CREATE TABLE dbo.FactSales ( ...
0
votes
1answer
62 views

FK Issue with Fact Table

I have a Datawarehouse star schema. One Dim table is 'DimTweet'. This contains tweet details. For a selected date I want to be able to display the number of tweets. However, I have a problem in my ...
0
votes
1answer
39 views

Storing mail in database, data type

I've found pretty poor informations about mail databases. My need is to archive mail messages downloaded from a normal pop3 or imap account: I am an ordinary user and I do not own the server, but ...
2
votes
1answer
23 views

Count of range on datetime in MySql

I want to group table entries for each userId only if they are consecutive entries in the table. I have a table like this. id userId transactionTime 1 1 2016-04-13 22:15:44 2 1 ...
2
votes
1answer
20 views

Multiple columns from one table rely on one single table

I'm working with PostgreSQL 9.2 and have the following relation between 2 tables: The table town stores a list of town codes. The table perimeter stores perimeters denomination. Towns are almost ...
0
votes
1answer
25 views

Design question

I want to implement an extension to my following table Object table == building in generall +--------+-----------+------+--------------+-----------+-------+------+ | obj_id | obj_ident | name | ...
0
votes
2answers
45 views

Multiple one-to-one relations

I'm trying to design database relations for archaeological places in a country. There are around 9000 places registered. An archaeological place can have multiple types. Types will be like Cave, Mound,...
5
votes
1answer
286 views

Why should I “Avoid partitioning dimension tables” on SQL Server?

SQL Cat have a list of tips titled Top 10 Best Practices for Building a Large Scale Relational Data Warehouse. Under section 4 - Design dimension tables appropriately they state: Avoid ...
2
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1answer
24 views

Avoid circular reference with configuration tables

I've got a few tables that define configuration information. This defines what combination are allowed in the system. However, I've got a circular reference on ProjectName which can cause potential ...
0
votes
2answers
91 views

Is it OK to use PRIMARY KEYs from one table as NAMEs of other tables?

My case: I have many organisms (for example human, mouse and etc.) and a few models for each one. All models are independent from each other and I will never query them together. Normally I will do ...
2
votes
1answer
52 views

Best Practice : Schema design for Large Number of rows with few columns

I have about a data set that each entry is about 750,000 rows under it with each row having four fields. Each entry is in its' own CSV file currently and I want to get it into a database. Currently I ...
2
votes
2answers
46 views

Advantage of exposing data model to customers using our product

We have a product through which we provide a standard definition to customer's asset data. The problem currently lies in importing customer's data from different types of data sources to our data ...