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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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3answers
532 views

Consequences of “naïve” vs “naive”?

While using IE autocorrect "naive" got transformed to "naïve"! My regional settings are Au English, from a Unicode search point of view the two are nothing alike. I am not even sure whether there are ...
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4answers
4k views

Can NoSQL databases be used in e-commerce companies for order management?

Is it possible to use a non relational database be in an Order management system for an e-commerce company with a large number of orders everyday, like Amazon? Can the benefits of Non Relational ...
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3answers
7k views

How to test data based on SQL queries?

I'm trying to set up a test framework for (SQL) datasets that get updated daily. I want to write assertions that involve comparisons between two tables–for example, the sum of column visitors in the ...
5
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2answers
284 views

Does it make sense to use a cursor for complex business logic?

I am dealing with a pretty extensive data set. After a few joins, the foundation table has something like 40 columns. The next 40 columns will all be calculated. I am trying to keep my Java clean of ...
5
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3answers
269 views

How to avoid mixing surrogate key with the rest of the data

Suppose you have a very simple CRUD where you are just storing a simple tuple-like type of data, but its natural primary key is cumbersome for the user to remember (very long, difficult to write, etc.)...
5
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1answer
740 views

What is Rainbow (not the CMS)

I was reading this excellent blog article regarding speeding up the badge page and in the last comment the author waffles (a.k.a Sam Saffron) mentions these tools: dapper and a bunch of custom ...
5
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3answers
690 views

Stored procedures or ORM in web?

I am working in a Peruvian company that develops desktop accounting software(.net C#). We have many clients (companies) each customer can create several companies, in addition there is a new database ...
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2answers
4k views

Why is NoSQL better for this scenario?

Hypothetical scenario: Let's say we are downloading JSON from Facebook with details of a user's friend's checkins, posts, etc... These come in as one document per friend per activity, so with 8 ...
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3answers
2k views

Should we have a database independent SQL like query language in Django?

Note : I know we have Django ORM already that keeps things database independent and converts to the database specific SQL queries. Once things starts getting complicated it is preferred to write raw ...
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3answers
2k views

Production-safe SQL stored procedure debugging

We have an enormous number of nested SQL stored procedures, and a number of different ways of debugging them (varying from developer to developer). So far, our methods include: An optional @debug ...
5
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2answers
171 views

What is the equivalent of functions and methods in SQL?

In language like C or Java, there are things like functions/methods to modularize and abstract stuff. What is there in SQL, specifically for Oracle? I've seen people talking about using views to ...
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2answers
168 views

What strategy should I employ using C# to solve this use case?

So this is all hypothetical and theoretical really. This isn't a real system I'd have to architect, but its a good question. A company stores and reproduces contracts. Contracts can have many ...
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4answers
4k 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 ...
5
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4answers
975 views

Designing a Database Application with OOP

I often develop SQL database applications using Linq, and my methodology is to build model classes to represent each table, and each table that needs inserting or updating gets a Save() method (which ...
5
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5answers
392 views

How can I store information with varying structure?

I'm having trouble coming up with a name for this problem, but I feel like its been solved before. I think my naiveté is preventing me from typing the right words into Google to get the results I need....
5
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1answer
989 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 ...
5
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2answers
473 views

Good architecture for user information on separate databases?

I need to write an API to connect to an existing SQL database. The API will be written in ASP.Net MVC3. The slight problem is that with existing users of the system, they may have a username on ...
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5answers
1k views

Alternatives for comparing data from different databases

I have two huge tables on separate databases. One of them has the information of all the SMS that passed through the company's servers while the other one has the information of the actual billing of ...
5
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1answer
775 views

OpenID implementation - PHP, Javascript, MySQL

I've started doing some research on the technologies that I will need for my website. I'm trying to implement a really simple website with OpenID user registration. The website will store a block of ...
5
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2answers
243 views

Is it worth implementing Entity Framework when calling a single stored select?

I'm currently building a web application for my enterprise level business internship. This web application will track data from three different sources: a DB2 database, a SQL Dynamic database, and an ...
5
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3answers
1k views

How to enforce the mandatory participation constraint at the many end in a one-to-many relationship?

Say I have the following ER diagram: Enforcing the mandatory participation constraint at the one end is easy, I simply make the foreign key (school_id) in Student NOT NULL. But how can I enforce the ...
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4answers
5k 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 ...
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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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8answers
15k views

Learning Java in a couple of days and preparing interview presentation [closed]

I know its not possible to 'know' or 'learn' Java fully in a couple of days but I really need some help on this guys. I have just graduated from university with a degree in computer science. The ...
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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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3answers
1k views

Why put SQL statement in a variable before using mysql_query()?

I'm been working with PHP on and off for a bit now, and I've seen plenty of code both ways: $sql = "SELECT …"; mysql_query($sql); vs mysql_query("SELECT…"); Is there a reason for separating the ...
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2answers
2k views

How deeply programmer should know about internals of database engine? [closed]

I am learning SQL Server 2012 along with C#. In the past, I took database class in college, and have good grasp on SQL language and can write queries. However, looking at SQL Server documentation (or ...
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4answers
371 views

Object Oriented Design and Relational Databases: Where to place behavior that pertains to more than one tables?

I have been trying to learn Object Oriented Design, but I find it very difficult to model objects that access a relational database and do JOINs. For example, I am building a REST API, it has User, ...
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2answers
507 views

Proper Data Structure for Commentable Comments

Been struggling with this on an architectural level. I have an object which can be commented on, let's call it a Post. Every post has a unique ID. Now I want to comment on that Post, and I can use ...
4
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3answers
412 views

Rule of thumb for field sizes

What VARCHAR sizes should be used for first and last names, phone numbers (preferably international), email adresses, urls, dictionary words and file names? Edit: Zapped the introductory phrase to ...
4
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3answers
5k views

How to reach to the advanced level in SQL? [closed]

I think I have a good grasp of SQL and the most features it has, but sometimes when I've done some more advanced Reporting Services a fellow developer has helped me with some stuff and when I open ...
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4answers
1k views

What are the arguments for/against Code Generation?

I'm in a position where we've got some brittle code that constructs SQL-like queries via text concatenation with parameters for inputs. The data source that it queries is fast and scalable but lacking ...
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5answers
590 views

Is it bad software design to mix JDBC SQL calls and use an ORM in an application? [closed]

Is it bad software design to have JDBC/raw SQL and also use an ORM? I don't mind using an ORM for boilerplate CRUD, but some queries are better in SQL (for me). I'm not arguing for or against ORMs. ...
4
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2answers
173 views

Why are dependencies typically reversed when representing complex objects as relational tables?

I'm going through some sort of phase where I over analyze and second guess every single decision I make when attempting to write software that has preventing me from getting anything done. I recently ...
4
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2answers
280 views

Is there some rationale behind SQL's lack of closure for what are standard operations in imperative languages?

Is there some historical or practical reason why SQL (or more specifically T-SQL in my case) does not support the closure property in many areas where many other language families like C do? (That is,...
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3answers
3k views

What to do with database foreign keys in an entity class?

I know that an attribute defines the state of an object. So, is it correct to keep attributes that don't define the state of an object of a class? For example, I have an Employee class, which has ...
4
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2answers
113 views

Why are triggers seen as a last resort to solve multiple paths in cascading deletes?

There is a problem using ON DELETE CASCADE on foreign keys in a SQL database if there are multiple paths from the root foreign key to the leaf. The way around this seems to be to replace the ON DELETE ...
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4answers
1k views

Multiple Joins or Simple Readable Database Calls

Curious how other developers feel about this. I come across some pretty nasty sql joins, as we all do I'm sure. I would prefer making more database calls for the sake of readability and simplicity ...
4
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3answers
872 views

How to avoid unmaintainable code when using SQL in an MVC setting?

I want to present a list of products to the user. This list is paginated and can be sorted by the user by product ID or product name in ascending or descending order. I am using an MVC setting, where ...
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6answers
2k views

How can I improve upon this “pattern”?

I have a series of method calls that all share similar qualities. The basic layout is public void CallDataBase() { Utility sqlHelper = new Utility(); StringBuilder query = new ...
4
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6answers
158 views

Arguments for storing binary asociations in a single field vs. in a mapping table?

When do you draw the line between relational tables, and fields holding multiple values of a particular type. Let me illustrate in an example below where a PokeMaster can be associated to multiple ...
4
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2answers
488 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; ...
4
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2answers
286 views

Having 2 Initialize Paragraphs in 1 COBOL program

I am designing a COBOL program that does 2 things. 1 reads specific rows from a table, and inserts a new row based on the original. 2 reads different rows from the same table, and updates those rows. ...
4
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2answers
262 views

Database constraints for a recursive folders structure

In an application, I have a recursive folder structure (like folders in OS X or Windows file system). Each folder can contain three kind of things: Other folders (hence the recursive structure) ...
4
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1answer
7k views

Web-app filtering information client-side vs server-side?

I have a web-app that provides data (that is updated on an interval) for intranet users, who are able to filter information by location. I was having a discussion with a co-worker about whether that ...
4
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3answers
370 views

How about multiple bits performance in common databases?

If there are 20 bit columns (non-null boolean), is it better to explicitly hold them in an integer type (int32)? Or, will the underlying database merge them in a single integer? I'm using PostgreSQL, ...
4
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2answers
6k 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 ...
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2answers
1k views

Best practice to represent SQL in program source code

Where SQL statements are executed from a program, what is the best practice to store the statement text? Most often it is in a read only string, in the source file it is executed in. I think a ...
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3answers
1k views

Appropriate use of SQL CLR

We have some back end processes that runs* on our sql server (SQL Server), they involve processing claims. This requires both data manipulation (biz logic) and data read/write to tables. The biz ...
4
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2answers
305 views

How to represent a collection with capacity in a database?

Concerning normalization of a one to many relationship, I am not sure how to represent a collection with a specified capacity in a database. I can think of two ways to represent an entity A with a ...