indeksistruktuur

An indeksistruktuur, or index structure, is a data structure that improves the speed of data retrieval operations on a database table. Without an index, a database system must scan every row in a table to find the specific information requested by a query. This can be very slow, especially for large tables. An index works similarly to the index in a book. It contains a sorted list of values from one or more columns of a database table, along with pointers to the actual rows in the table where those values are located.

When a query is executed that includes a condition on an indexed column, the database can use the index to quickly locate the relevant rows. Instead of scanning the entire table, it can look up the desired value in the sorted index and then follow the pointers to retrieve the data. Common types of index structures include B-trees, hash indexes, and full-text indexes, each suited for different types of queries and data. The choice of index structure can significantly impact query performance.

However, indexes are not without their drawbacks. They consume storage space and can slow down data modification operations, such as inserts, updates, and deletes, because the index also needs to be updated. Therefore, it is important to carefully consider which columns to index and to use indexes judiciously to balance retrieval speed with modification overhead.