Kyselykäsittelijä

Kyselykäsittelijä is a Finnish term that translates to "query handler" or "query processor." In the context of computer science and databases, it refers to a component or program responsible for receiving, parsing, validating, and executing queries submitted by users or other applications. The primary function of a kyselykäsittelijä is to translate a user's request, often expressed in a query language like SQL, into a series of operations that a database management system (DBMS) can understand and perform.

When a query is submitted, the kyselykäsittelijä first checks its syntax to ensure it conforms to the rules of the query language. It then verifies that the query is semantically correct, meaning that it refers to valid tables, columns, and other database objects. After successful validation, the kyselykäsittelijä may optimize the query to find the most efficient way to retrieve or modify the requested data. This optimization process can involve choosing appropriate indexes or reordering operations. Finally, the kyselykäsittelijä sends the optimized query to the database engine for execution, and then returns the results to the requester. Different systems may have varying levels of sophistication in their query handlers, impacting performance and the types of queries they can efficiently process.