Category: Database Concepts

Signed vs Unsigned Integers

Posted on by Ian

The integer data type is probably one of the more common data types when working with database management systems (and with computing in general). The integer is a numeric data type that allows us to store certain kinds of numbers.

More specifically, an integer is the number zero (0), a positive natural number (e.g. 1, 2, 3, …) or a negative integer with a minus sign (e.g. −1, −2, −3, …). Integers contain no decimal or fractional part.

However, many computing environments distinguish between signed integers and unsigned integers.

Let’s take a look at the difference between signed integers and unsigned integers.

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What is a Comparison Operator?

Posted on by Ian

Comparison operators are an important part of most programming languages.

Comparison operators are used to compare two expressions. The result is either true or false. It could also be unknown. This could also be represented by either 1, 0, or NULL, depending on the language. These are typically known as “Boolean expressions”.

When used with databases, comparison operators can be used inside your SQL queries to filter data to a certain criteria.

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What is the Year 2038 Problem?

Posted on by Ian

The Year 2038 problem (also referred to as the Y2K38 bug) refers to a problem that some computer systems might encounter when dealing with times past 2038-01-19 03:14:07.

Many computer systems, such as Unix and Unix-based systems, don’t calculate time using the Gregorian calendar. They calculate time as the number of seconds since 1 January 1970. Therefore, in these systems, time is represented as a big number (i.e. the number of seconds passed since 1970-01-01 00:00:00). This is typically referred to as Epoch time, Unix time, Unix Epoch time, or POSIX time. As I write this, Unix time is 1560913841. And as I write this next line, Unix time has incremented to 1560913879.

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What is Collation in Databases?

Posted on by Ian

In database systems, Collation specifies how data is sorted and compared in a database. Collation provides the sorting rules, case, and accent sensitivity properties for the data in the database.

For example, when you run a query using the ORDER BY clause, collation determines whether or not uppercase letters and lowercase letters are treated the same.

Collation is also used to determine how accents are treated, as well as character width and Japanese kana characters. Collation can also be used to distinguish between various ideographic variation selectors in certain collations (such as the Japanese_Bushu_Kakusu_140 and Japanese_XJIS_140 collations that were introduced in SQL Server 2017).

Different database management systems will provide different collation options. Depending on the DBMS, collation can be specified at the server level, the database level, the table level, and the column level. Collations can also be specified at the expression level (so you can specify which collation to use when you run a query), and at the identifier level.
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“This Data” vs “These Data” – Which is Correct?

Posted on by Ian

If you happen to read a lot of data-related material, you might occasionally find the word “data” being treated in different ways. In some cases you’ll see “this data is…” and in other cases “these data are…”.  You might even think “they obviously made a mistake with their grammar”.

Not so fast!

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What is OLAP?

Posted on by Ian

OLAP (Online Analytical Processing) is a category of database processing that facilitates business intelligence.

OLAP provides analysts, managers, and executives with the information they need to make effective decisions about an organization’s strategic directions. OLAP can provide valuable insights into how their business is performing, as well as how they can make improvements.

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What is Normalization?

Posted on by Ian

Normalization is the process of organizing a database to reduce redundancy and improve data integrity.

Normalization also simplifies the database design so that it achieves the optimal structure composed of atomic elements (i.e. elements that cannot be broken down into smaller parts).

Also referred to as database normalization or data normalization, normalization is an important part of relational database design, as it helps with the speed, accuracy, and efficiency of the database.

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