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.

learn more… | top users | synonyms

0
votes
1answer
65 views

Do Temporary tables have any form of index in SQL?

Consider a simple query like this: SELECT * FROM DATA JOIN ( SELECT * FROM DATA )TEMPORARY_DATA ON TEMPORARY_DATA.DATA_IDN = DATA.DATA_IDN What is the performance of this? Is it O(n2) because ...
14
votes
5answers
4k 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 ...
2
votes
2answers
222 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 ...
2
votes
1answer
202 views

Mental schema for SQL queries [closed]

While preparing SQL introductory material, I've ended asking myself about the line of thought followed by a developer when writing a query. I believe it could be too valuable from a beginner's point ...
0
votes
1answer
67 views

Is there any reason not to allow negative numbers to be entered into a JSP field labeled for positive numbers?

Our application, a fairly complicated money ledger, has a JSP field for entering a certain type of money due, balanced by payments made towards that amount due. In the application, this field is ...
7
votes
4answers
2k views

C# database communication technique

A few days ago, I read an answer stating that writing queries within your c# code are long gone. I'm not sure what the specific person meant with the comment but, it got me thinking. At the company ...
4
votes
2answers
607 views

Where to put a common database connection for my classes

I have several classes (Repositories) which do the task of saving/retrieving some objects in/from database; all of them need to establish a connection to one database. I thought in order to avoid ...
23
votes
6answers
1k views

Does the advent of the SSD have any implication for database optimization?

Today I was browsing through a book on SQL Server optimization and it seemed that a certain amount of the ideas were based on a linear model of storage. As SSDs have a completely different storage ...
24
votes
9answers
9k views

Using JOIN keyword or not

The following SQL queries are the same: SELECT column1, column2 FROM table1, table2 WHERE table1.id = table2.id; SELECT column1, column2 FROM table1 JOIN table2 ON table1.id = table2.id; And ...
-3
votes
1answer
155 views

Finding next free IP in a network

I have an IP network and want to automatically find a free IP address to provision a new server. Due to frequent server additions/removals the used IPs might be quite fragmented over the whole address ...
-4
votes
4answers
4k views

How to not let anyone inspect elements of a webpage?

I was thinking to make some jQuery functions that will use ajax to control mysql. The whole idea is to make separate files of PHP (e.g query.php, addRow.php, update.php and delete.php) provide data to ...
22
votes
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 ...
2
votes
2answers
102 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 ...
1
vote
0answers
57 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 = ...
3
votes
2answers
126 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 ...
10
votes
6answers
1k views

Why is SQL known as a relation-based / functional language?

We're learning that most languages are classified as either of the two, "relation based" or "high level". I've never used SQL before, but from reading its syntax it seems more like the ...
0
votes
2answers
42 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
vote
1answer
55 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: ...
1
vote
1answer
92 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. ...
0
votes
0answers
59 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: ...
6
votes
7answers
557 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
votes
1answer
121 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
votes
1answer
160 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 ...
1
vote
1answer
349 views

Creating a online database creator

I've been thinking of creating an online database creator (think DabbleDB, Zoho Creator, Intuit Quickbase, etc.). I've been thinking of a couple solutions: Have 4 database tables: Tables, Rows, ...
5
votes
3answers
386 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 ...
1
vote
0answers
259 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; ...
1
vote
2answers
901 views

Database Context and Singleton injection with IoC

All of the below relates to a ASP.NET c# app. I have a Singleton Settings MemoryCache that reads values from database on first access and caches these, then invalidates them using SQL Service Broker ...
4
votes
2answers
115 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
2answers
93 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 ...
1
vote
0answers
246 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
1answer
263 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
3answers
335 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
vote
2answers
705 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. ...
2
votes
1answer
547 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 ...
4
votes
2answers
367 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
votes
1answer
44 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 ...
1
vote
2answers
842 views

SQL injection attacks, how do I test and secure coldfusion queries?

I'm running Coldfusion 8 and SQL server 2008. I've been building serveral forms that insert data into the database from external users, we have a custom built security module built by the guy who ...
3
votes
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 ...
0
votes
3answers
509 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 ...
19
votes
6answers
43k views

SQL Triggers and when or when not to use them.

When I was originally learning about SQL I was always told, only use triggers if you really need to and opt to use stored procedures instead if possible. Now unfortunately at the time (a good few ...
-1
votes
2answers
305 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 ...
0
votes
2answers
1k 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 ...
3
votes
3answers
427 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 ...
4
votes
1answer
1k views

How to translate SQL query into REST API requests?

Let's say I have a machine-readable description (such as in WADL, Swagger or RAML) of a REST API that provides interface to a database. My users submit queries about underlying database in form of ...
3
votes
3answers
631 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
2answers
99 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 ...
10
votes
4answers
1k 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. ...
0
votes
1answer
48 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 ...
4
votes
4answers
667 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 ...
2
votes
5answers
282 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 ...