In the world of database management systems (DBMSs) and computer programming, CRUD is an acronym that stands for Create, Read, Update, and Delete. These are considered to be the four basic operations of persistent storage.
Let’s take a look at how CRUD fits into database management systems and programming in general.
When using relational database management systems (RDBMSs) we often hear terms like DDL, DML, DQL, DCL, and TCL. But what exactly are they?
In this article we’ll look at what TCL stands for in the context of SQL, and what it does.
When using relational database management systems (RDBMSs) we often hear terms like DDL, DML, DQL, TCL, and DCL. But what exactly are they?
In this article we’ll look at what DCL stands for in the context of SQL, and what it does.
We often hear terms like DDL, DML, DQL, TCL, and DCL when using relational database management systems (RDBMSs). But what exactly are they?
In this article we’ll look at what DQL stands for, and what it does.
We often hear terms like DDL, DML, DQL, and DCL when using relational database management systems (RDBMSs). But what exactly are they?
In this article we’ll look at what DML stands for, and what it does.
We often encounter terms like DDL, DML, DQL, DCL, and TCL when using relational database management systems (RDBMSs). But what do they mean?
In this article we’ll look at what DDL stands for and what it does.
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.
If you’re new to relational databases, and you’re trying to get your head around this concept of a “relationship” in your database, I hope this article helps.
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.
In database terms, a CHECK constraint is a type of constraint that checks data before it enters the database.
CHECK constraints help maintain data integrity, because they prevent invalid data entering the database.