Struct SchemaRegistry 

pub struct SchemaRegistry { /* private fields */ }

Thread-safe registry of table schemas.

All tables that should be replicated from OLTP to OLAP must be registered here with their Arrow schema and primary key definition.

Implementations

impl SchemaRegistry

pub fn new() -> Self

Create an empty SchemaRegistry.

pub fn register(&self, schema: TableSchema) -> Result<(), CoreError>

Register a TableSchema.

Calls TableSchema::validate before inserting. The registry holds an Arc clone of the schema so subsequent get calls are cheap.

Errors

Returns CoreError::TableAlreadyRegistered if a table with the same name is already present. Returns CoreError::SchemaValidation if validation fails.

pub fn get(&self, table_name: &str) -> Result<Arc<TableSchema>, CoreError>

Look up a TableSchema by table name.

Returns an Arc clone — the call is cheap and does not copy the schema.

Errors

Returns CoreError::TableNotFound if table_name has not been registered.

pub fn table_names(&self) -> Vec<String>

List all registered table names.

pub fn unregister( &self, table_name: &str, ) -> Result<Arc<TableSchema>, CoreError>

Remove a table from the registry and return its schema.

Errors

Returns CoreError::TableNotFound if table_name is not registered.

pub fn update(&self, schema: TableSchema) -> Result<(), CoreError>

Replace an existing table’s schema in-place (used during schema evolution).

Validates schema before replacing. Does not apply DDL to any engine; callers must also call the corresponding OlapEngine::add_column / OlapEngine::drop_column methods.

Errors

Returns CoreError::TableNotFound if the table is not registered. Returns CoreError::SchemaValidation if the new schema is invalid.

pub fn add_column( &self, table_name: &str, column_name: &str, data_type: DataType, ) -> Result<Arc<TableSchema>, CoreError>

Add a nullable column to a registered table’s schema.

The column is appended at the end of the field list. New columns are always marked nullable so that existing rows (which lack the column) remain valid.

Returns the updated schema arc.

Errors

Returns CoreError::TableNotFound if the table is not registered. Returns CoreError::SchemaValidation if column_name is invalid or already exists.

pub fn drop_column( &self, table_name: &str, column_name: &str, ) -> Result<Arc<TableSchema>, CoreError>

Remove a column from a registered table’s schema.

Returns the updated schema arc. Note that the SQLite OLTP engine requires CDC triggers to be torn down before issuing DROP COLUMN (SQLite rejects DROP COLUMN while triggers reference the column).

Errors

Returns CoreError::TableNotFound if the table is not registered. Returns CoreError::SchemaValidation if column_name is a primary key column or does not exist in the schema.

impl SchemaRegistry

pub fn save_to_disk(&self, path: &str) -> Result<(), CoreError>

Persist the current registry contents to a JSON file at path.

The file is written atomically via a temp file + rename so a crash mid-write cannot produce a corrupt file.

Errors

Returns CoreError::SchemaValidation if serialization fails or the file cannot be written or renamed (e.g., permission denied, disk full).

pub fn load_from_disk(path: &str) -> Result<SchemaRegistry, CoreError>

Load a previously persisted registry from a JSON file at path.

Returns an empty SchemaRegistry if the file does not exist (fresh start). This design means that the first run behaves identically to subsequent runs — no special-casing is needed at call sites.

Errors

Returns CoreError::SchemaValidation if the file exists but cannot be read, is not valid JSON, contains an unknown Arrow type string, or contains schemas that fail TableSchema::validate.

Trait Implementations

impl Clone for SchemaRegistry

fn clone(&self) -> SchemaRegistry

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for SchemaRegistry

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for SchemaRegistry

fn default() -> Self

Returns the “default value” for a type.