Struct ProjectionDb 

pub struct ProjectionDb;

A SQLite pool initialised from a DDL schema string.

The pool is the projection read model — event handlers write to it, API handlers read from it via plain SQL queries.

Schema versioning is handled automatically via a SHA-256 content hash. App developers only write domain tables in their schema.sql; the _schema bookkeeping table is owned by this library.

In-memory

ProjectionDb::in_memory creates a fresh database on every process start and applies the schema immediately. State is populated by replaying the full operation log.

On-disk

ProjectionDb::open opens (or creates) an on-disk database. On startup it compares the hash of the supplied schema against the stored hash. If they differ the database is wiped, the new schema applied, and the caller is expected to replay all operations before serving traffic.

Implementations

impl ProjectionDb

pub async fn in_memory(schema_sql: &str) -> Result<(SqlitePool, bool), Error>

Create a new in-memory SQLite pool and apply schema_sql.

The _schema table is created and populated automatically. App developers should not include it in their schema file.

pub async fn open( path: &str, schema_sql: &str, ) -> Result<(SqlitePool, bool), Error>

Open (or create) an on-disk SQLite database.

If the stored schema hash differs from the hash of schema_sql, all user tables are dropped and the schema is re-applied. Returns true if a rebuild occurred (signalling that the caller should replay ops).