A database management system (DBMS) is a software for managing a [[database]]. Popular DBMS include Microsoft Access, [[MySQL]], [[Postgres]], and noSQL databases like [[MongoDB]]. Contrast to a file system that represents a collection of individual files accessed by individual applications. The data are separate, isolated, often duplicated, inconsistent, and not joinable (imagine a collection of spreadsheets in a file system like Google Drive). A DBMS ensures consistency and referential integrity facilitating effective and efficient data storage. The primary downside to a DBMS is the complexity excludes most users from interacting directly with it without developing a custom UI. (Although in many cases this is a benefit as it helps preserve data integrity). [[buffer cache]]