Questions tagged [sql]

Structured Query Language (SQL) is a language for managing data in relational database management systems. This tag is for general SQL programming questions; it is not for Microsoft SQL Server (for this, use the sql-server tag), nor does it refer to specific dialects of SQL on its own.

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1answer
142 views

structure problem in Relational DBMS creation

For learning and understanding purpose, I currently want to try to make a small relational DBMS with simple features like (for now) only sequential reading/writing and CREATE TABLE, INSERT, SELECT, ...
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2answers
10k views

SQLite with two python processes accessing it: one reading, one writing

I'm developing a small system with two components: one polls data from an internet resource and translates it into sql data to persist it locally; the second one reads that sql data from the local ...
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4answers
5k views

Database is performing slow, even all the tables are having normalization

An interviewer asked me this question: Tables are created with appropriate normalization rules, However the database is performing slow. [Ie.: The select, insert statements are taking time to do ...
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1answer
2k views

C# Design for SQL connection and commands

Currently I'm working on system that works with database, and I would like to have it done elegant way. So I have abstracted DBConnection into one class, DBCommands into another class. (DBCommands : ...
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7answers
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Nested Entities and calculation on leaf entity property - SQL or NoSQL approach

I am working on a hobby project called Menu/Recipe Management. This is how my entities and their relations look like. A Nutrient has properties Code and Value An Ingredient has a collection of ...
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4answers
5k views

Why many designs ignore normalization in RDBMS?

I got to see many designs that normalization wasn't the first consideration in decision making phase. In many cases those designs included more than 30 columns, and the main approach was "to put ...
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2answers
3k views

Best practice in application design / SQL authentication

I am currently involved in the implementation/design of an existing application for a large scale customer. The application has a similar model as e.g. vCenter Server whereby a number of components ...
2
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5answers
13k views

Using Autoincrement Primary keys as Foreign Keys

When creating a table, there is an option for us to set the numeric primary key as autoincrement where its value increases whenever a new data in inserted. This primary number can be used for ...
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10answers
6k views

Why don't RDBMSes return joined tables in a nested format?

For example, say I want to fetch a User and all of his phone numbers and email addresses. The phone numbers and emails are stored in separate tables, One user to many phones/emails. I can do this ...
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2answers
564 views

Automating database deployment using a CMS

My team are developing Umbraco websites and looking to improve the automation of our database deployment. Currently we have automated builds and deployments of our source code using Kiln and Team ...
0
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2answers
440 views

Best practices for rotating large datasets?

[edit]Turns out there's 1.5 million records... The SQL database is taking about 17-20 seconds to run the query. Would it be best to have Java handle the joins and rearranging in that case? Since this ...
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1answer
721 views

What's the best approach to building a db schema for profile, but to track changes?

I'm working on a site where companies can create a profile then add locations for each profile. Those first two tables are simple enough. But any changes to their profiles or locations have to go ...
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2answers
2k views

Logic design question for SQL query

Was wondering if you could help me on a SQL problem I’m having. I have a set of records of events where each event has a start time and end time. No event has the same start time, and the end time ...
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5answers
9k views

Is SQLite a sensible option for data logging?

I am trying to setup a small data-logging application under linux. The data arrives via serial port, and from there it should be pumped to logging and to graphical display. The logging functionality ...
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1answer
2k views

Status update & news feed database design / architecture

Imagine a application similar to Facebook, where you have status updates and a news feed. The names and profile pictures can be changed. There are also several different types of updates requiring a ...
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1answer
1k views

Different ways to generate the latest int type primary foreign key in code

I am new to sql. I have added 2 new tables in database. The primary key of first is a foreign key in the other. The type of the keys is integer. Now I want to generate the keys in the code and assign ...
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2answers
7k views

In what order are rows fetched absent ORDER BY clause?

One programmer is testing and comparing the same application which uses the same database structure, and the same data, only in two separate databases, one with Oracle 8 and one with Oracle 9. The ...
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1answer
1k views

Are there any SQL servers that support compiled queries?

Can SQL queries be compiled into byte code or equivalent to enhance performance? I know that most database servers support prepared statements, but is that the same thing as compiling? Most ...
29
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1answer
53k views

JOIN vs. INNER JOIN and FULL OUTER JOIN

I know there is a difference between INNER JOIN and FULL OUTER JOIN, I can see it, but, what is the difference between the two following: JOIN ... ON... and INNER JOIN...ON... and still yet JOIN...ON.....
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2answers
22k views

SQL IN() versus OR

I was working with a query I wrote today had to change the code from the WHERE clause to use a IN(list of stuff) filter instead of using something like item_desc = 'item 1' OR item_desc = 'item 2' OR ...
3
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1answer
1k views

Rewriting C# Formula Calculations in T-SQL

We have a 3-tier application with a C# client that connects to a C# web service via WCF and requests data from a SQL Server database. One feature in our application is a user-created form app in ...
3
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5answers
402 views

Need thoughts on a course curriculum for an entry-level programmer [closed]

Would love to know your thoughts on a curriculum that will be developed for people that want to get started in the programming field. The goal of the course is to help it's students to ensure that ...
1
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1answer
312 views

What is better: multiple sql entries or one sql entry with a list field?

Suppose that I have the following logical information: (tag_name, id). For example: (food, 1),(food, 2),(food, 3),(drink, 1),(drink, 2) I'm trying to decide what is the best way to store it in a ...
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2answers
81 views

Working with data and meta data that are separated on different servers

While developing a product, I've come across a situation where my group wants to store meta data for data entry forms (questions, layout, etc) in a different database then the database where the ...
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4answers
16k views

C# Minimal SQL Database

I'm working on a small project (not production) where I'm needing to store enough data that something like a CSV would be inefficient to process and an SQL/MySQL server would be too much. Does .Net ...
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1answer
1k views

Advanced Search Stored procedure

So I am working on an MVC ASP.NET web application which centers around lots of data and data manipulation. PROBLEM OVERVIEW: We have an advanced search with 25 different filter criteria. I am using a ...
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6answers
21k views

At what size of data does it become beneficial to move from SQL to NoSQL?

As a relational database programmer (most of the time), I read articles about how relational databases don't scale, and NoSQL solutions such as MongoDB do. As most of the databases I have developed ...
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2answers
2k views

Clustering Strings on the basis of Common Substrings

I have around 10000+ strings and have to identify and group all the strings which looks similar(I base the similarity on the number of common words between any two give strings). The more number of ...
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1answer
791 views

Formatting SQL statements [duplicate]

In recent years I've developed a habit of formatting SQL SELECT queries like so: SELECT fieldNames FROM sources JOIN tableSource ON col1 = col2 JOIN ( SELECT ...
2
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1answer
223 views

Testing MVC models when using SQL referential constraints

I have an MVC web app that's wired against PostgreSQL. The DB uses the full gamut of various referential constraints to ensure referential integrity, as opposed to say the Rails approach, where you ...
22
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2answers
9k views

Is SQL declarative?

I ask because so many of the questions I see in SQL amount to: "This is slow. How do I speed it up"? Or are tutorials stating "Do this this way and not that way as it's faster". It seems to me that a ...
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1answer
90 views

SQL Table Design Modification based on data roles or implementation convenience?

I've got an existing SQL table structure that looks like this: Orders - order_id - organisation_id - [all the rest of the order data] Organisations - organisation_id - [all the rest of the ...
2
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1answer
1k views

How can I maintain a SQL schema upgrade that goes out to our users on a regular basis?

I work on a project that uses a SQL database as a back end, and a desktop app as a front end. We do releases on a regular basis, and as part of a release, our client needs to update their SQL server. ...
3
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2answers
4k views

Saving user profiles in SQL database

So, I got a table UserProfiles in my database, that, similar to C#'s Settings file, holds a property with the appropriate datatype and the specified setting in the profile. Now each time I add a new ...
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3answers
1k views

Protect Database Design - SQL

Perhaps a bit of an odd question but I can't think of a way to achieve what I want. I produce a product which ends up installed on-site at clients premises. It is a business critical and high ...
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1answer
1k views

What is the proper and easy way to move a LocalDB to Azure using code first ?

The only way I could figure how to do it was create the schema on the localDB with code first and then manually change the database string to Azure and then run the code on Azure.. But that only ...
2
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4answers
2k views

How to genericize foreign key references in table?

I am trying to design a table to store references to multiple tables as a "target" of the item in each row. An example should clarify what I am trying to do: Imagine you have 4 tables (images, videos,...
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2answers
12k views

Best place to write SQL queries

I've been working on this project for my company. Currently I am embedding my SQL statements inside the program itself as and when they are needed. I do have two seperate classes - QueryBuilder ...
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1answer
155 views

Visual Studio DBProjects and problem with it running post-build SQL (file too big)

What I am doing is creating a DBProject.. importing a DB.. then creating scripts in the PostBuild that are DATA scripts for each table (so that the post build can populate the tables after the schema ...
4
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6answers
2k views

OOP (php) for beginners - some unclarities

I started reading some tutorials about OOP, because I want to learn the basics. I have a question about it. I understand how you can have a object "Car" and give it a color like this $oCar->setColor("...
2
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2answers
381 views

Best strategy in SQL

Recently, a colleague told me that it wasn't advisable to make conditions in the join clauses. Instead he suggested to make conditions in the where clause. He told me that the SQL engine was optimized ...
0
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2answers
280 views

ACID compliant Database that isn't NoSQL? [closed]

I'm not necessarily asking if a NoSQL database can be ACID compliant, which has been asked here: Is there any NoSQL that is ACID compliant? I'm wondering if we have a database either now or in the ...
1
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2answers
269 views

Are error codes wrong in SQL queries too?

I have an SQL query which does several things at once¹: it does multiple checks and then, if the checks pass, updates some data. Without entering in the domain-specific details, here's an imaginary ...
3
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2answers
774 views

Referencing countries via Foreign Key Constraint

To make things simple to explain: I've got two tables: Table1 and Countries. The Countries table contains a nice flag and some information, such as DisplayName, the ISO3166 ALPHA3 code and the phone ...
2
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2answers
650 views

Not using SQL Transactions

I am looking at a codebase where a developer never uses SQL transactions i.e. each update/insert into the SQL database is an atomic operation. I believe the codebase would benefit from transactions. ...
5
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1answer
999 views

Designing a universal database driver class

I have a homebrew MVC framework that I have been using for a while, and it has been working great, but I am planning an upgrade to it for its ORM classes. So far, it only supports SQL databases by ...
1
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4answers
353 views

Create a database for database tables

I'm working on a project where I have to give users the ability to build their own tables, each user can create more than one table. (the type of all data is string). The user can create a table and ...
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1answer
4k views

Why do we still use a programming language instead of using just SQL? [duplicate]

In database managements systems lecture, my professor said that we can use Oracle etc. ui designing tools instead of using Visual C# or etc. He added that SQL is as strong as a programming language. ...
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2answers
238 views

Should I retrieve one large set of data to filter or smaller individual sets of data?

I have a company intranet that utilizes a similar set of data across many different pages and many different methods. Speaking in generalities, is it closer to "best practice" to retrieve a large ...
107
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4answers
73k views

why are noSQL databases more scalable than SQL?

Recently I read a lot about noSQL DBMSs. I understand CAP theorem, ACID rules, BASE rules and the basic theory. But didn't find any resources on why is noSQL scalable more easily than RDBMS (e.g. in ...