indeksatsioonid

Indeksatsioonid, or indexing, is a fundamental concept in computer science and information management, referring to the process of creating a data structure that allows for faster retrieval of information from a larger dataset. Essentially, it's like creating an index for a book, enabling users to quickly locate specific information without having to read through the entire volume. In databases, indexing is crucial for improving the performance of queries. When a table is indexed, specific columns are associated with a separate data structure, often a tree-like structure like a B-tree or a hash table. This structure stores the values from the indexed column along with pointers to the corresponding rows in the main table.

When a query searches for data based on an indexed column, the database can use the index to efficiently pinpoint the relevant rows. Instead of scanning every row in the table (a full table scan), which can be very slow for large tables, the database navigates the index to find the matching entries and then directly accesses the required data. This significantly reduces the amount of data that needs to be read and processed, leading to faster query execution times. However, indexing is not without its costs. Creating and maintaining indexes requires additional storage space and can slow down data modification operations like inserts, updates, and deletes, as the index also needs to be updated. Therefore, choosing which columns to index and when to use indexing is a critical aspect of database design and optimization.