Memory pointers when navigating database structures. Write data, database operations translate these refs from offsets to As Realm Database uses memory mapping to read and Refer to data using the offset from the beginning of the file. Since pointers refer to memory addresses, objects written to persistentįiles cannot store references as pointers. Each column uses one value size, determined by the largest Columns are arrays of data with uniformly sizedĬolumns store data in one of the following sizes: 1, 2, 4, 8, 16, 32, Each contains a rangeĬlusters store objects as collections of columns.Įach column contains data for a single property for multiple instances Leaves on the Cluster Tree are called Clusters. The top level, known as a Group, stores object metadata, a transactionĮach class in the realm schema corresponds to a Table within theĮach Table contains a Cluster Tree, an implementation of a B+ tree. Organizes these data structures into a tree structure with the following Groups, Tables, Cluster Trees, and Clusters. Realm files contain object data with the following data structures: Management files, suffixed with "management", e.g. :file``:Įnable inter-thread and inter-process notifications. That is still used by a client application. This prevents realm from reclaiming storage space Keep track of which versions of data in a realm areĪctively in use. Realm Database persists data in files saved on device Make queries faster than an ORM, and often faster than raw SQLite. Realm Database uses a zero-copy design to Unindexed, but querying a single field across multiple objects orįetching multiple objects can be much faster due to spatial locality and Individual objects can be slower than row-based storage equivalents when Realm Database stores objects as groups of property values. Not separate different object types into individual tables. In a SQL database table or a MongoDB document. Each object in a realm is equivalent to a row You can think of each realm as aĭatabase. Realm Database stores data in realms: collections of Realm Database controls optimizations from the storage level all Realm Database's underlying storage layer usesī+ trees to organize objects. Scratch in C++, instead of building on top of an underlying databaseĮngine like SQLite. Realm Database is an entire database written from With Device Sync and the local version of Realm Database. Realm Database, and wraps up with some of the differences of working This explanation begins with a deep dive into database internals,Ĭontinues with a high-level introduction to some of the features of Trying to understand how Realm Database works with This page is for you if you are:Ī developer interested in learning more about Realm DatabaseĬomparing Realm Database with competing databases This page explains some of the implementation details and inner workings Mobile: designed for the low-power, battery-sensitive, real-time Just define a schema for each SDK you use. Object-oriented: organizes data as objects, rather than rows,Ĭross-platform: use the same database on iOS, Android, Reactive: query the current state of dataĪnd subscribe to state changes like the result of a query, or even Realm Database is a reactive, object-oriented, cross-platform, Copy-on-Write: The Secret Sauce of Data Versioning.
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