I have a simple setter method for a Java property and null is not appropriate for this particular property. I have always been torn, in this situation: should I throw an IllegalArgumentException, or a NullPointerException? From the javadocs, both seem appropriate. Is there some kind of understood standard? Or is this just one of thos...
We have our own ORM we use here, and provide strongly typed wrappers for all of our db tables. We also allow weakly typed ad-hoc SQL to be executed, but these queries still go through the same class for getting values out of a data reader. In tweaking that class to work with Oracle, we've come across an interesting question. Is it bette...
I am in the middle of reading the excellent Clean Code One discussion is regarding passing nulls into a method. public class MetricsCalculator { public double xProjection(Point p1, Point p2) { return (p2.x - p1.x) * 1.5; } } ... calculator.xProjection(null, new Point(12,13)); It represents different ways of handling t...
Is there a performant equivalent to the isnull function for DB2? Imagine some of our products are internal, so they don't have names: Select product.id, isnull(product.name, "Internal) From product Might return: 1 Socks 2 Shoes 3 Internal 4 Pants ...
I was wondering if there is a better way to cope with MS-Access' inability to handle NULL for boolean-values other than change the column-data-type to integer. ...
Does any one have a preference on how to check if a value is DBNull? I've found these two statements give me the results I want, but just wondering if there's a preference? if (any is System.DBNull) ... same as: if (any == System.DBNull.Value) ... Thanks! Ricardo. ...
It's my understanding that nulls are not indexable in DB2, so assuming we have a huge table (Sales) with a date column (sold_on) which is normally a date, but is occasionally (10% of the time) null. Furthermore, let's assume that it's a legacy application that we can't change, so those nulls are staying there and mean something (let's s...
In Java, I use a class in which some fields can be null. For example: class Foo { String bar; //.... } I want to write a BarComparator for this class, private static class BarComparator implements Comparator<Foo> { public int compare( final Foo o1, final Foo o2 ) { // Implementation...
This issue came up when I got different records counts for what I thought were identical queries one using a not in where constraint and the other a left join. The table in the not in constraint had one null value (bad data) which caused that query to return a count of 0 records. I sort of understand why but I could use some help fully g...
I am told that good developers can spot/utilize the difference between Null and False and 0 and all the other good "nothing" entities. What is the difference, specifically in PHP? Does it have something to do with ===? ...
When a Java VM crashes with an EXCEPTION_ACCESS_VIOLATION and produces an hs_err_pidXXX.log file, what does that indicate? The error itself is basically a null pointer exception. Is it always caused by a bug in the JVM, or are there other causes like malfunctioning hardware or software conflicts? Edit: there is a native component, this ...
I need to do a comparaison between an object and NULL. When the object is not NULL I fill it with some data. Here is the code : if (region != null) { .... } This is working but when looping and looping sometime the region object is NOT null (I can see data inside it in debug mode). In step-by-step when debugging, it doesn't go i...
The Interwebs are no help on this one. We're encoding data in ColdFusion using serializeJSON and trying to decode it in PHP using json_decode. Most of the time, this is working fine, but in some cases, json_decode returns NULL. We've looked for the obvious culprits, but serializeJSON seems to be formatting things as expected. What else c...
There's a school of thought that null values should not be allowed in a relational database. That is, a table's attribute (column) should not allow null values. Coming from a software development background, I really don't understand this. It seems that if null is valid within the context of the attribute, then it should be allowed. This...
If I want to construct a std::string with a line like: std::string my_string("a\0b"); Where i want to have three characters in the resulting string (a, null, b), I only get one. What is the proper syntax? ...
What's the best way to create a non-NULL constraint in MySQL such that fieldA and fieldB can't both be NULL. I don't care if either one is NULL by itself, just as long as the other field has a non-NULL value. And if they both have non-NULL values, then it's even better. ...
I have a method that is suppose to return an object if it is found. If it is not found, should I: a) return null b) throw an exception c) other ...
In the early days of C++ when it was bolted on top of C, you could not use NULL as it was defined as (void*)0. You could not assign NULL to any pointer other than void*, which made it kind of useless. Back in those days, it was accepted that you used 0 (zero) for null pointers. To this day, I have continued to use zero as a null pointer...
What is the best way to convert an int or null to boolean value in an SQL query, such that: Any non-null value is TRUE in the results Any null value is FALSE in the results ...
We noticed that lots of bugs in our software developed in C# (or java) cause a NullReferenceException. Is there a reason why "null" has even been included in the language? After all, if there were no "null", I would have no bug, right? In other words, what feature in the language couldn't work without null? ...