36 lines
2.1 KiB
Markdown
36 lines
2.1 KiB
Markdown
# Overview
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`co3` is a lightweight Python ORM for hierarchical storage management. It implements a
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general type system for defining database components like relations, schemas, engines,
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etc. Objects inheriting from the `CO3` base class can then define data transformations
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that connect to database components, and can be automatically collected for coordinated
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database insertion.
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`co3` attempts to provide a general interface for interacting with a storage media (e.g.,
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database, pickled objects, VSS framework, in-memory key-value stores, etc). The following
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top-level classes capture the bulk of the operational model:
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- **Database**: reference to a storage medium, with an `Accessor` for accessing data,
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`Manager` for managing database state, and an `Engine` for managing connections and
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external operations.
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- **Accessor**: provides access to stored items in a `Database`, typically via a supported
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`select` operation over known `Component` types
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- **Manager**: manages database storage state (e.g., supported inserts or database sync
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operations)
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- **Mapper**: associates `CO3` types with `Schema` components, and provides automatic
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collection and composition operations for supported items
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- **Collector**: collects data from defined `CO3` type transformations and prepares for
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`Database` insert operations
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- **Component**: atomic storage groups for databases (i.e., generalized notion of a
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"relation" in relational algebra).
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- **Indexer**: automatic caching of supported access queries to a `Database`
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- **Schema**: general schema analog for grouping related `Component` sets
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- **Differ**: facilitates set operations on results from selectable resources (e.g.,
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automatic comparison between file data on disk and file rows in a SQL database)
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- **Syncer**: generalized syncing procedure for items between data resources (e.g.,
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syncing new, modified, and deleted files from disk to a SQL database that stores file
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metadata).
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The **CO3** an abstract base class then makes it easy to integrate this model with regular
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Python object hierarchies that can be mapped to a storage schema.
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