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

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0
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16 views

how to remove create relation foreign key in phpmyadmin

I am having problems in PhpMyAdmin Designer Section. I'm not able to do anything like I cant even move them to see their relations. When I try to click on tables the screen shown in picture appear ...
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1answer
159 views

Name of a descriptive text field? [closed]

I have seen descriptive text field named as DESCRIPTION, REMARK, and NOTE. They seem to mean the same thing. So what is more appropriate than the others?
1
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0answers
17 views

Conceptual data model for warehousing objects [duplicate]

I'm student and new to databases. I must conceptualize a database model for warehousing video games using a relational database management system (MySQL). Every objects in the warehouse have common ...
1
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1answer
36 views

Multitenant application: several tables or several IDs?

We are designing a common product to serve several companies. The most convenient way to do this, technically speaking, is to deliver a database to each customer. But we predict that, depending on ...
1
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0answers
22 views

How to design for scalable set operations?

This is the requirement for an educational application to teach words to language learners: Learner can declare that he/she knows a given word Learner can memorize the given word (to be managed by ...
7
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3answers
665 views

Blockchain (Bitcoin) as a database?

I was reading this BBC News article and the following excerpt, caught my attention. It sounds like Always On Availability Groups or High Availability Mirroring, maybe with security automatically ...
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1answer
25 views

database design help with multiple table relationships

Been scratching my head on how to set this up and looking for your help. Trying to create an API and not 100% how my tables should relate to one another. So lets say I have users, food, and food ...
1
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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 ...
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1answer
51 views

Slot Time Challenge - Doctor Appointment database schema

I am trying to make a doctor appointment system where patient online will have two options: First time visit (this visit should be 20 mins) Follow up visit (this visit should be 10 mins) ...
7
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2answers
100 views

Transposing hierachical data from one VARCHAR to two INTs

THE PROBLEM The table where the data is recorded is CREATE TABLE [dbo].[Almoxarifado]( [idAlmoxarifado] [varchar](20) NOT NULL, [tipoAlmoxarifadoId] [varchar](30) NOT NULL, [entidadeId] ...
1
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1answer
40 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 ...
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0answers
51 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
28 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 ...
5
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2answers
67 views

Postgres Update Limit

I'm curious if Postgres has anything in place where I could limit the amount of rows kept for a ID. For example, say I have a users table and login_coordinates table. Every time the user logs in, ...
3
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2answers
63 views

When do you know that you've made a design flaw in a SQL/relational database?

I've been working with a a relational model for a work project over the last few months, and I've gotten to the point where I'm wondering if I've made a mistake in my model's design or implemented ...
5
votes
2answers
276 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 ...
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0answers
20 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
50 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 ...
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 ...
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0answers
18 views

3NF For a Weak Entity with no non-Key attributes

Can a weak entity made with no non-key attributes be in 3NF? I'm making a db for an assignment, and I currently am struggling to figure this out, especially since I've introduced auto-increment ...
2
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1answer
75 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 ...
1
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1answer
29 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 ...
-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 ...
0
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1answer
37 views

How to create a table in access and automatically fills it with information from a query? [closed]

Is it possible if I create a table that will lookup for a value filtered from a query (consult), in this case is duplicated "Name"s from a Employees registring table and automaticly fills up that ...
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0answers
12 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
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0answers
51 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 ...
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0answers
23 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 ...
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1answer
32 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
32 views

what prerequisite are required to become a DBA?not overview but to the depth of course [duplicate]

what prerequisite are required to become a DBA?not overview but to the depth of course if any online link is there to learn or course to become DBA then let me know
2
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0answers
46 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 ...
7
votes
2answers
154 views

Normalizing a table with a field that generally uniquely identifies a row, but is sometimes null

forgive me if this has been asked and answered before. I'm roughing out a schema for an inventory management system, to be implemented in PostgreSQL. All of our products and services have a sku. ...
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0answers
17 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?
2
votes
1answer
51 views

How do I guarantee inventory numbers are unique across all tables?

I have an assortment of physical objects which need to be inventoried and each type of object has it's own table. For two example objects, let's use 'swords' for the table containing different swords ...
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0answers
27 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
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 ...
0
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1answer
45 views

Foreign key as part of composite primary key or not?

I'm designing a relational database. This is what I'm trying to design: I will have production orders and products. A production order will have one product, but a product could be on zero or more ...
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0answers
15 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 ...
3
votes
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 ...
2
votes
1answer
70 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 ...
3
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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, ...
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0answers
15 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
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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

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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1answer
40 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 ...
0
votes
1answer
61 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 ...
0
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1answer
60 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 ...
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 ( ...
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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
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 ...
0
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1answer
24 views

Design question

I want to implement an extension to my following table Object table == building in generall +--------+-----------+------+--------------+-----------+-------+------+ | obj_id | obj_ident | name | ...