Final answer:
Existing fields in a database or programming environment are critical when used with expression operators as they contain the data these operators manipulate. Calculations, comparisons, and other data manipulations are facilitated through the combination of fields and operators, enabling advanced data handling and querying capabilities.
Step-by-step explanation:
In the context of computers and technology, existing fields serve a crucial function when used with expression operators within a database or programming environment. Operators are symbols or keywords that tell the computer to perform specific mathematical, relational, or logical operations and return a result. The existing fields, which are the columns of data within a table in a database or variables in a program, hold the data that these operations act upon.
For instance, when performing a calculation with an arithmetic operator like addition (+), the existing fields might store the values that are to be added together. When using a relational operator such as greater than (>), the existing fields provide the values to be compared.
In summary, existing fields when coupled with expression operators enable users to manipulate, compare, and compute data efficiently, leading to dynamic and powerful data handling capabilities. These fields are essential in data manipulation, querying databases, and creating expressions that aid in decision-making processes within applications.