A nested loop is a logical structure used in computer programming and coding. It is characterized by two or more repeated statements that are placed in a “nested” manner, meaning that one repeated “loop” or command is contained within the body of the other. It is an efficient and, in most cases, relatively simple way for coders and programmers to cause sequential events and actions that complement each other through a series of interrelated commands and signal returns. Nested loops are a common part of most computer programs, but can also be found in many situations where technology intersects with the presentation of some kind of information.
Nested loops are logical structures used in a wide variety of computer programs.
Because it is used
The loop is a powerful construct in programming as it allows you to quickly sort or input large amounts of data efficiently. Solving problems in the business world, for example, or in manufacturing, often involves repeating an action indefinitely with hundreds, thousands, or even millions of individual pieces of data. As a result, loops are constructs that are often used in all kinds of computer programs in all kinds of industries.
A nested loop is a powerful and easy way for coders and programmers to cause sequential events and actions that build on each other.
Relationship between loops
The outer loop and each and every inner loop are related to each other in important ways. They are not only connected, but also receive signals from each other and depend on each other to translate and complete various digital signals and tasks. Specifications tend to vary by application, but almost constant communication is almost always guaranteed.
In most cases, the outer loop is what causes the inner loop to execute. The inner loop repeats as many times as specified in the code or materials of the command. When the inner loop completes, the outer loop runs through its second iteration, triggering the inner loop again, and so on until the requirements for the outer loop are complete.
Many computer programmers work in Structured Query Language (SQL), and nesting is of particular relevance here. Essentially, it provides a means by which a person can quickly and efficiently look up data in two linked tables. An outer loop is used to read the first table, one row of data at a time; then the data needed to look up the second table is passed to the inner loop, which reads the second table. As a result, the loop can process two linked tables efficiently. Most of the time, all of this happens almost instantly.
different levels
The most basic cycle has only two levels, though things can and often do get much more complicated. More than two loops can be nested, and they can go as deep as needed to do a given job. An easy way for many people to visualize the concept is by analogy with a car odometer. Imagining the leftmost digit of the odometer as the outermost cycle is the best way to start; from there, each successive digit can be considered another loop, one inside the other, until the rightmost digit is reached, which represents the innermost nested loop. In most cases, the more nesting there is, the more complex the underlying code or command will be.
How loops are configured
The exact looping process and initial structuring vary between programming languages. In SQL, for example, a programmer can write these structures and execute them as a server-side nested loop that is called remotely or as one on a client machine that is executed locally. To use these powerful structures effectively, it is necessary to take into account both the language used by the program and the database or other backend that is queried for the data.
