This tag is for general database questions; if you question is specific to SQL use that tag instead.

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0
votes
2answers
53 views

Retry method for generating unique code

In an app, a user can initiate the generation a six-digit alphanumeric code (actually done via Web API). The code needs to be checked against a remote database to ensure it is unique. Other than for ...
-4
votes
0answers
64 views

about source code that I developed by a developer [on hold]

I got developed some software for me by a developer abroad. They agreed when giving the work that they will give us source codes and database back up files. But now they are not giving us . they are ...
-4
votes
0answers
14 views

Skype message_oid in database [on hold]

Can someone tell me how to find the "message_oid" number for a message in a skype database? Or how to find it in any way. Please help. Thanks a lot.
-2
votes
0answers
15 views

how to make an interactive databaseplatform [on hold]

Hi i have a bunch of information on excel spreadsheets, however i want to turn this into an interactive searchable platform online so my clients can easily navigate the infomation, what kind of ...
5
votes
1answer
158 views

Log to file or to database table?

I'm developing a web application which uses MS SQL for various data: including users, user accounts, user licenses, license prices, invoices. I need to log users' real-time usage of the system, and ...
7
votes
3answers
171 views

How to model and store an entity which has “one or more” values

I'll use C# to design the model to be persisted Let's suppose I have the following entity: public class Episode { public int Id { get; set; } public string Title { get; set; } public ...
1
vote
1answer
70 views

More than 20 Records Inserted in a Span of 1 Sec

Well, this is not specific to any programming languages. I came across this situation in Android, iOS, PHP and .NET. The problem is many times I come across a situation while building IoT apps, where ...
0
votes
0answers
72 views

Dealing with several custom getters

I have a data structure with data units containing different types of data. I've wrapped the data in "Field" objects so that each field is able to independently parse user input in a desired way. ...
-2
votes
0answers
11 views

Mysql fulltext match character limit [migrated]

I'm using following query to select most relevant 10 keywords for an article. I use this weird approach because there are 50 million keywords in the table. It's slow but it works good enough for my ...
-1
votes
1answer
76 views

What should my approach be to tagging 10 million articles based on relatedness? [closed]

I have 50 million tags and 10 million articles in mysql db. I want to tag each article with 5 related tags. Tags have 1 to 6 words. Mostly there are 3 words in a tag. I think most accurate and ...
2
votes
1answer
143 views

Matching algorithms in context of data quality problems

I work for an organization that has lots of databases containing person information. The data quality is poor. One case was a surname I found like this (this is the worst-case scenario): Mark ...
2
votes
3answers
130 views

Best approach for storing huge data

I'll be handling 300,000+ users. Each user (after logging in) will be able to create lets say "folders", in each folder, users will create "name=value,name2=value2,name3=value3" entry pairs. Each name ...
0
votes
1answer
90 views

Designing a scalable schema for college database [closed]

I am trying to build back end for college ERP system. The system will be based on LAMP. These is the scenario: Colleges have 5 branches There are 4-6 classes in each branch. There are 80 students ...
0
votes
1answer
22 views

online database with partial access for clients

I'm trying to come up with an online database that my clients would have partial access to. This is for an artwork storage company. We have about 40 clients and would like each to have access to their ...
2
votes
0answers
69 views

is there a way to tell JDBC I am about to execute a transaction? [migrated]

when setting AutoCommit to false; is this means that I have to commit after executing every sql command in my application. here is a scenario SQL1 doesn't need to be a transaction. SQL2 needs to ...
1
vote
1answer
47 views

Creating a separate table for images or adding “image fields” to many tables?

I need to create a database in which several tables have images. For example, users have profile pictures and uploaded ones and products have many pictures, as well. Is it better to have one MySql ...
4
votes
2answers
95 views

Using audit trail as time machine?

I would like to do SELECT * TABLE t (using data from 1st of march 2012) I already have a nice audit trail of all tables in the database. It basically makes a copy of all rows that change, storing ...
0
votes
1answer
57 views

How can I iterate over two loops of mismatched sizes, keeping them in sync?

I have a database table in which each row is one movie (with fields like 'title', 'director' and 'writer'), and a related table where each row is one screenshot from a movie (with the fields ...
3
votes
0answers
88 views

Why there is a drop of interest in DBMSs? [closed]

I was playing around with google trends explorer when I tried to compare three major DBMSs: MySQL, Oracle and MS SQL Server. As you can see there is a drop in the interest in these database ...
2
votes
1answer
87 views

Multiple websites and applications using one user database

I've got several applications and websites that will be built around one main application. In a perfect situation users will be able to register once and be able to log into the different applications ...
2
votes
2answers
188 views

architecture of database heavy application

A program I'm currently designing is extremely database heavy, almost anything the user does will alter the database, or read from it. Now I have one interface which defines all these operations, and ...
4
votes
3answers
114 views

How to track temporal changes in a database?

Imagine a software for theater owners. You can accept reservations for the different cinema halls. Each hall has a different number of seats. Say the owner wants to know how many people visited the ...
4
votes
4answers
204 views

How to prevent race conditions in a web application?

Consider an e-commerce site, where Alice and Bob are both editing the product listings. Alice is improving descriptions, while Bob is updating prices. They start editing the Acme Wonder Widget at the ...
3
votes
2answers
205 views

Why Do B+ Trees Have a Minimum Occupancy of 50%?

As far as I can tell, the basic operations (add, delete, search) on a B+ Tree would function the same if minimum occupancy was 1, or 1/3, or any other function on node size. All the sources available ...
2
votes
0answers
46 views

String comparison equivalence between mysql database and php code [migrated]

I wonder if it is possible to compare two strings using mysql and php and obtain the same results. In mysql I have a = b collate utf8_general_ci For PHP I found a promising way to do it with the ...
0
votes
1answer
123 views

calculating the average of a value over a month [closed]

I am working on a project right now that is having me calculate monthly interest on a bank account. The way the interest is supposed to be calculated is as follows: Use the daily average to calculate ...
-1
votes
0answers
21 views

Does a database update force index rebuild regardless of updated field? [migrated]

With MySQL (InnoDB), I understand that having indexes slow down UPDATE queries. I would like to know if this happens regardless of what fields are updated. For example, if I have a table with 20 ...
0
votes
0answers
34 views

Entity Framework Lookup Tables

I am coming from working with ADO.net DataSets and feel fairly comfortable with how they work. Mainly, I usually have a DATA table with a large number of REF tables for lookups. In DataSets it was ...
0
votes
0answers
26 views

Syncing structured data and files in Android App with an ORM?

I am developing an Android App which I have developed for iOS before. The app requires that structured data and files are synced across android devices. In iOS, I was using Core Data and synced to ...
2
votes
2answers
38 views

Bulk update in client-server application

Sometimes when coding a client-server application, the client needs to make a bulk update. For example: "mark all pending orders as dispatched". To implement these I typically write specific ...
0
votes
0answers
9 views

compare different approachs for saving related records whose values may change

On a web application for accounting services, I have the good old Invoice. To keep this example as simple as possible, each Invoice has many rows, and each row has its item with its price. At the ...
2
votes
1answer
68 views

Managing Database version controlled migrations using a list/table

I'm not much of an expert in the area but I am aware that solutions already exist to managing database migrations in version control, e.g. sqitch and liquibase. However I'm currently planning a small ...
0
votes
0answers
47 views

Automatically verifying INSERTs when building a PHP(5.3.3) application

I am building a form in PHP. I would like to automatically verify that INSERT queries are successful, and populate data correctly, as opposed to running queries in Workbench or MySQL with every code ...
1
vote
1answer
32 views

Proper tree NoSQL structure with focus on full-text searching

I developing an app with tree(folder-file) structure, on which I should perform full-text searches with MongoDB. I did a research on the best tree structure practices and found this great article, but ...
2
votes
3answers
162 views

What are the advantages/disadvantages of creating a new set of tables for each user?

I'm working/playing on an app where individual users' data will be completely independent from each other. Of course, there will be common tables for other parts of the app (e.g. "users"), but for the ...
0
votes
1answer
79 views

Would it make sense to have a database table with only one record for tracking site summary stats?

I'm creating a web site that deals with monetary transactions. Users can deposit funds into a wallet and use them on the site. I'd like to keep track of some stats for the web site, like revenue and ...
2
votes
2answers
132 views

Designing a system to archive databases with referential integrity

I have a very large Oracle database, with many many tables and millions of rows. I need to delete some of the rows end-to-end. By end-to-end, I mean, if I want to delete a row from a table then I must ...
0
votes
0answers
62 views

When to use a message queue as a web service database?

Does it make sense to implement a message queue system such as RabbitMQ or Kafka for the purpose of storing data in a queue? For example, this could be done in order to handle things such as ...
1
vote
0answers
70 views

Entity Framework Code First Centralized database deployment

I originally posted this on stack overflow but was told that here is a better place to ask this kinda stuff. I couldn't find any other similar answered question but if there is one please give me a ...
2
votes
3answers
111 views

What is a Database Environment?

I am going through Relational Database Design by JLM. I have come across words like database, data model, DBMS etc. which I am able to understand. But, I get confused when the author tries to use ...
1
vote
1answer
40 views

Reduce Operations on Distributed Databases

I would like to ask you about optimizing reduce operations (e.g. count) on multiple databases. Let's say there is a user table that is stored in various countries and sharding is made based on the ...
2
votes
2answers
167 views

Separation of retrieving data and business objects between DAL and BLL Layers

I did some research before posting this question. Among other questions or post, one of those is provided below. I could not get a clear mind how to determine.. Business Objects within a Data Access ...
3
votes
1answer
90 views

Fixing bad data in a database - redo or incremental

I have pseudo-ownership of a fairly old db (original data from 30 years ago; current design is >15 years old). In my opinion, the schema is pretty broken, and one of the implications of this is that ...
1
vote
1answer
93 views

Normalization 3NF and BCNF

If I have the following relation R = (A, B, C, D) And the functional dependencies: A -> B, B -> A, CDB -> A, CDA -> B The candidate keys are CDA and CDB. The third normal form says that ...
13
votes
3answers
2k views

Database schema for a ToDo list

I am trying to make a very simple todo list application with PHP, MySQL, Jquery templating and JSON... However, my schema seems to complicate things in JSON. What's the best way to do it? A new ...
2
votes
5answers
84 views

Using DDL commands in programming language [duplicate]

Hello I am a student with no industry experience. My question may sound dumb, but, me and my friends were having discussions on use of DDL directly in programming language (any language may be Java, ...
6
votes
4answers
384 views

Heterogeneous Associations - Data Modeling When an Object that Must Relate to One of Many Classes

Suppose you have 3 classes: ClassA, ClassB and ClassC. Now suppose you have a class Message. You want a one-to-many relationship between each one of those three classes and the Message. The goal is ...
1
vote
3answers
159 views

Database design: 4 types of users but have different functionality , separate or one table?

I have 4 types of users: Admins , normal user , company , service provider admins and normal user share some attributes (id .first name ,last name ,phone ,mail) company and service provider share ...
1
vote
1answer
63 views

How to associate both a collection and one item of this collection to an entity

I'm working on a project in which I have an entity, we may call Users and another entity Address. I want to define the entity User in a way that an user would have a collection of addresses ...
1
vote
1answer
118 views

What is the point behind building an abstraction layer PDO Adapter class instead of using native PDO?

I have built a PDO adapter class because I thought, at the time anyway, it would be a good idea. After fighting with it, it makes no sense to me. Isn't the design of PDO the way it is to keep you ...