Why was null a mistake?

Null is not polymorphic with any object so any function that invokes it will break the chain of subsequent calls. This has led to innumerable errors, vulnerabilities, and system crashes.

Was the null pointer a mistake?

Speaking at a software conference in 2009, Tony Hoare apologized for inventing the null reference: I call it my billion-dollar mistake. It was the invention of the null reference in 1965. At that time, I was designing the first comprehensive type system for references in an object oriented language (ALGOL W).

Why do people hate null?

The problem with NULL is that it is a non-value value, a sentinel, a special case that was lumped in with everything else. Instead, we need an entity that contains information about (1) whether it contains a value and (2) the contained value, if it exists.

Is null a bad idea?

It may return NULL instead of an object—that's what is wrong. NULL is a terrible practice in an object-oriented paradigm and should be avoided at all costs.

Why null is a problem in Java?

Problems with the null Pointer in Java

The NullPointerException is a common bug frequently encountered by every programmer in Java. This error is raised when we try to dereference an identifier that points to nothing – this simply means that we are expecting to reach some data but the data is missing.

Null References The Billion Dollar Mistake

Why should null values be avoided?

Even though many database administrators use NULL, they usually demand that NULLs are not used for numeric values. The reason is that NULLs used for numeric values can become confusing when developing code to calculate data.

What are null values and why are they a problem?

A null value in a relational database is used when the value in a column is unknown or missing. A null is neither an empty string (for character or datetime data types) nor a zero value (for numeric data types).

Is null always false?

Comparing any variable with NULL will always evaluate to FALSE, regardless if it's value, unless IS NULL or IS NOT NULL is used. Violating this rule will affect the functionality of the code. The severity is critical which means that the code will not function correctly.

What happens if you write to null?

The null device acts like a black hole. Anything written to it is discarded, and if you try to read from it you receive an end-of-file immediately.

What can I use instead of null?

Empty String

String data types are often initalized to null as well. However, for the exact same reasons, we prefer to use an empty string to replace null .

What does it mean WTF is NULL?

Null means having no value; in other words null is zero, like if you put so little sugar in your coffee that it's practically null. Null also means invalid, or having no binding force. From the Latin nullus, meaning "not any," poor, powerless null is not actually there at all. Or if it was, it's gone now.

Why is NULL not false?

The way you typically represent a “missing” or “invalid” value in C# is to use the “null” value of the type. Every reference type has a “null” value; that is, the reference that does not actually refer to anything.

Why is NULL 0 false?

Comparisons convert null to a number, treating it as 0 . That's why (3) null >= 0 is true and (1) null > 0 is false. On the other hand, the equality check == for undefined and null is defined such that, without any conversions, they equal each other and don't equal anything else. That's why (2) null == 0 is false.

Why is null a million dollar mistake?

The language could have been designed without it. Tony Hoare , the inventor of null (in ALGOL) calls it a “billion dollar mistake”: This has led to innumerable errors, vulnerabilities, and system crashes, which have probably caused a billion dollars of pain and damage in the last forty years.

Is null true or false?

The null value represents the intentional absence of any object value. It is one of JavaScript's primitive values and is treated as falsy for boolean operations.

What is the point of null?

A NULL value is a special marker used in SQL to indicate that a data value does not exist in the database. In other words, it is just a placeholder to denote values that are missing or that we do not know. NULL can be confusing and cumbersome at first.

Is returning null a bad practice?

It's very tempting to just return a null reference, but this could cause problems for the caller. If the caller(or callers), fails to do a null check, it could result in a NullPointerException being thrown if some value from the item object is used.

Is null actually blank as character?

Blank (or space) is a character. Zero is a number. Null means "no value".

Is the null never true?

An often heard criticism of null-hypothesis significance testing is that the null is always false. The idea is that average differences between two samples will never be exactly zero (there will practically always be a tiny difference, even if it is only 0.001).

Does null mean unknown?

NULL indicates that the value is unknown. A null value is different from an empty or zero value. No two null values are equal.

What is true about null?

null means that the value is unknown null stands for the empty value null is a member of only the domain of integers nulls are not allowed in SQL true AND null is true null is a member of only the domain of strings.

What is NULL conditions?

The null condition tests for nulls, when a value is missing or unknown.

How do you solve NULL problems?

The #NULL! error is quite rare in Excel, and is usually the result of a typo where a space character is used instead of a comma (,) or colon (:) between two cell references. This error may seem baffling to the average user, but in most cases replacing the space with a comma or colon will fix the problem.

What is the problem with NULL in database?

Although NULL values represent "nothing" or "no value", they are treated as a value by the database. As such, they take up space on the hard drive. So, if you think that you are saving hard drive space by employing NULL values, you could be mistaken.

When should something be not null?

The NOT NULL constraint is used to ensure that a given column of a table is never assigned the null value. Once a NOT NULL constraint has been defined for a particular column, any insert or update operation that attempts to place a null value in that column will fail.