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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MS SQL DB retrieve two coloumns from one query [migrated]

I have two tables as below: Students table work table: My query is: select stud_name from students inner join work on work.library=students.stud_id where work_id=2 It returns name of ...
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0answers
56 views

Where should business logic involving SQL go? [duplicate]

I have this question that's been bugging me all day. I have a function like this: public void voidUsersByUserId(List<Integer> userIds) { Query query = ...
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1answer
66 views

How do you unit test \ use TDD methods for ETL's and reporting projects?

ETL projects are projects created using an ETL (Extract - Transform - Load) tool such as SSIS, PowerCenter,etc These typically involve reading data from an external source, loading it to a staging ...
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0answers
14 views

How to interpret correlated subqueries? [migrated]

Correlated subqueries are highly confusing me. Example query from here: SELECT DISTINCT store_type FROM stores WHERE EXISTS (SELECT * FROM cities_stores WHERE ...
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2answers
2k views

NoSQL within SQL Server

This question is not about the difference between SQL and NoSQL. I am looking for some rationale for something that really does not make sense to me at the moment (maybe because of my lack of ...
3
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2answers
94 views

How to infer the result of a query?

To understand what a query does, I have always thought the following is the procedure on evaluating a query: Form the table as specified in the FROM clause. Pick the rows from that table as ...
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2answers
34 views

SQL - for some attributes specific to different clients' users, how to handle schema?

I have clients, each of whom have an app with a bunch of users. Their user data could be pretty different, but there is also a lot of overlap. Ex: all their users have "gender" and "age" and plenty ...
1
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1answer
36 views

Object Storage where Object Type is variable

From time to time, we come across a problem where we must store an object, but we don't know in advance what kind of object we're going to store. I'm going to give a very simple example. Requirement: ...
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1answer
65 views

Sanity check SQL [closed]

Is there any tools/processes to check SQL does not contain any possible issues. For example we had an SQL ran that forgot to put a where clause on an update and mistakenly updated the entire table. ...
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0answers
52 views

How to deal with requests that don't conform to the existing data structure?

The system I'm working on has a list of assets that belong to different customers of the company. This data is saved on an SQL database. Removing irrelevant data, let's say the table is like this: ...
2
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2answers
72 views

Is using triggers best solution for this scenario

A large SQL transactional database has more than 100 tables (and it will grow). One of them is called Order. Then, there is another table WorkLoad which derives from Order and many other joined table ...
6
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7answers
289 views

How would you design a user database with custom fields

This question is around how should I design a database, it can be relational / nosql databases, depending on what will be the better solution Given a requirement where you'll need to create a ...
0
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1answer
57 views

Always set form input max length?

Background I'm looking to put together a single page web application with many form inputs. I've run into issues with other web pages where there is an ugly SQL error sent to the user if the ...
0
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1answer
158 views

Injectable, Poppable Stack

Background A project involves converting a relational expression map (rxm) to an XML/SQL statement. The map resembles: root > people, # "root" keyword starts the document ...
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0answers
24 views

How to use an Address Gazatteer in an application that contains addresses [closed]

Say I had access to the post office address file (http://en.wikipedia.org/wiki/Postcode_Address_File) and wanted to cleanse about one million addresses. I am trying to think of an "algorithm" to do ...
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3answers
256 views

SQL - Algorithm for finding availability of a resource

I'm having trouble creating a mysql compatible algorithm for this. Background App with mysql, perl and JS. It's a booking system where each booking is comprised of a start, end and qty. Start and ...
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0answers
78 views

Preserving Pre-formatted Multi-Line Strings in Node.js Scripts

There is a lot I don't like about PHP, but one thing I love is multi-line strings: $query = <<<EOT select field1 ,field2 ,field3 from tableName where field1 = 123 EOT; ...
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0answers
160 views

What is the “correct” way to store functions in a database?

Note: Yes, I know that storing functions in databases should be punishable by law. We are developing a financial web application using PostgreSQL, Sinatra and AngularJS. As you may have guessed, a ...
3
votes
2answers
70 views

Integration tests of SQL logic

In my daily work, I use a lot of SQL logic (oracle stored procedures and SQL functions). To limit the code regression on the implemented code I make what I call "integration scripts" : C# scripts that ...
4
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2answers
89 views

Use of NOLOCK on Microsoft SQL Server

The (NOLOCK) optimizer hint is well known by most SQL developers for setting the isolation level so that tables with rows or escalated page locks can be read. I've always known about the bad and ugly; ...
3
votes
1answer
217 views

Is a series of OR or a single IN SQL statement better?

I'm using MS SQL 2008 R2. I have been using a series of OR and have an issue where my app periodically give the following error: Exception message: Timeout expired. The timeout period elapsed prior ...
1
vote
2answers
242 views

How should I compare two database tables - with SQL or using Java? [closed]

I have two tables with different structure. I should compare ID from 1st table with ID of the intermediate table and then comapre TXT field of the intermediate table with TXT field of the 2nd table. ...
3
votes
2answers
211 views

Software development - The industry & general trends / Bad practices [duplicate]

I am a Web Developer and part of a small team working on an abundance of projects. This is my first "actual" real company after graduating with a degree in computer Science and I have about 2 years ...
0
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1answer
35 views

Merging user activities into one stream with a common representation

My social network website currently has forum threads and posts gallery pictures albums on the users' profiles group discussions classifieds I would like to create one "stream" of activity. It ...
3
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2answers
1k views

One of my team members committed SQL injection-vulnerable code; should I report it to the manager? [closed]

One of my team members committed a huge mistake; a clear SQL injection-vulnerability. It obviously didn't pass my peer review and I made very clear that this is unacceptable. I never saw this ...
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3answers
307 views

Using SQL queries in loops

Is it a bad idea? I need to compare each entry.Key value in a Dictionary of strings to a SQL table. If there is a match, then I pull the data from that row. I was originally going to use a foreach ...
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10answers
3k views

Is there any material difference between queries joined by WHERE clauses, and queries using an actual JOIN?

In Learn SQL the Hard Way (exercise six), the author presents the following query: SELECT pet.id, pet.name, pet.age, pet.dead FROM pet, person_pet, person WHERE pet.id = person_pet.pet_id ...
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2answers
155 views

Storing Dates & Times in SQL [closed]

I have a tool that I am working on which allows people to create meetings. They can select the Date, Time & Timezone that this meeting is occurring in. I need to determine the best way to store ...
2
votes
1answer
248 views

Should I use foreign keys in my database if I use laravel?

I'm creating a website with Laravel for the first time. I checked relationships documentation today and it seems that Laravel just uses simple SQL queries. class User extends Eloquent { public ...
3
votes
3answers
384 views

What kind of user info is ok to be stored as plain text in SQL Database?

I'm practicing around building e-commerce asp.net applications that allows for users to register to the site and their user credentials are stored in a MySQL database. In my sample project the ...
0
votes
2answers
722 views

Clients connect to WCF or SQL Server

I was wondering what is the prefered way of accessing data from a server in a client application. The data will be stored on the server in an SQL database and I have previously used the following 2 ...
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vote
1answer
140 views

Implementing “Trending Items” using linear regression in SQL Server

I'm building an MVC .NET website where people can rate and review movies (similar to IMDb). I'm using SQL Server for the back-end. I'll be implementing a feature where the homepage displays trending ...
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2answers
82 views

Sending a notification to each participant 3 hours before the meeting starts

Let's assume an application that deals with meetings where some users will participate. What is an efficient way to achieve this use case: 3 hours before the meeting should start, one reminder mail ...
3
votes
1answer
272 views

What is the best way to format complex SQL queries in Node?

I am using node-mysql to query a MySQL database via Express and Node. My queries are getting fairly complex and I want to format them across multiple lines. However, the only way I could accomplish ...
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4answers
864 views

Historical precedent for why Prolog is less popular than SQL in Imperative Programming? [closed]

It seems that writing Declarative SQL is very popular in Imperative Programming. However, it also seems that writing Declarative Prolog could save a lot of complexity but this is not very common. ...
3
votes
3answers
416 views

ASP.NET MVC should I reference the DAL from the UI?

I am developing an ASP.NET MVC application, and I have three projects: UI (with the system.web.mvc reference, BL and DAL references) BL (business facade and business objects) DAL (contains my ...
0
votes
1answer
44 views

Django Project Logic Solution

I'm starting to develop my first webapp, and I'm using django. Before anything I'm working on the software logic, how it should work, the links and objects it needs. The problem is: I need the app ...
2
votes
5answers
217 views

Stored Procedures, ORMs and other application layers

I'm just starting out on a project to develop a new, fairly substantial web application which has an underlying MSSQL database. We're hiring a team of developers to write the application (in .NET) and ...
2
votes
2answers
209 views

An algorithm that spreads similar items across a list

I need an algorithm that distributes same items across a list, so maximizing the distance between occurrences. E.g. I have a list of 15 items: {a,b,c,c,c,d,e,f,f,f,g,h,h,i,j} The algorithm should ...
31
votes
3answers
1k views

Why is most SQL written in YELLING? [duplicate]

On MySQL at least, the following two queries are functionally identical: select * from users limit 0, 1000; SELECT * FROM users LIMIT 0, 1000; However, most example sites and most developers I've ...
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2answers
59 views

Efficient database access for related data

As an example for this question, consider a content management system that has a content database table which contains things like the page title and location as well as the content itself which could ...
1
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3answers
291 views

Best OOP pattern to use for creating a commandline SQL API for a proprietary json based company datastore

We need to create a SQL commandline tool for querying a proprietary json based datastore. I'll be using java. Any suggestions on the primary OOP design pattern I should use for building this API? ...
-1
votes
1answer
582 views

SQLDatabase: Read a lot of data at once and process in memory or read the data when I need it?

I'm not sure how to approach this problem. I require a big chunk of data records from the SQL server. This chunk is based on variables, so I don't know before what records I need. I need to do a large ...
1
vote
1answer
104 views

Database choice [closed]

I am working on a system where I am replacing and existing Cobol system with C#. For the database I have hit some requirement which I am having a hard time to find complete support for (tried SQLite ...
3
votes
3answers
230 views

Is there a 'standard' SQL that can replace all the various custom versions?

I have been writing SQL for over 10 years now. I am extremely proficient at it and have experience working in SQL Server, Oracle, MySQL, PostgreSQL, etc. While there are multiple standards out there, ...
2
votes
2answers
140 views

Combine union with distinct

Situation: I need distinct results from two tables, that both have duplicates. I would like to know if I should combine UNION and DISTINCT. Example 1 - Only use distinct SELECT DistinctValue FROM ...
15
votes
4answers
4k views

Databases: Where should the application logic run? [duplicate]

http://highscalability.com/blog/2010/11/9/facebook-uses-non-stored-procedures-to-update-social-graphs.html talks about how Facebook moved logic out of the database into the application in order to ...
4
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4answers
478 views

Organise C++ classes around SQL database

My question is about how best to organize C++ classes around a database model, and I understand this may appear very elementary. The software I propose to create will do the following. It is intended ...
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0answers
68 views

An algorithm to implement SQL's ORDER BY with TOP/LIMIT or OFFSET/FETCH

Is there a general algorithm to implement SQL's ORDER BY with OFFSET/LIMIT more efficiently than sorting all the records? The algorithm for a simple TOP x is easy enough. It takes one full pass ...
2
votes
0answers
253 views

Separation of concerns between repository and service in DDD with complex entities

This probably seems as an example of opinion-based question, but I'm actually looking for rationale on how to decide correctly, I believe there is a correct solution that can be backed by solid ...