Enum Backend 

pub enum Backend {
    Mysql(MysqlBackend),
    Postgres(PostgresBackend),
    Sqlite(SqliteBackend),
}

Concrete database backend — dispatches to the active variant.

Only one instance exists for the program lifetime, so the size difference between variants is irrelevant.

Variants

Mysql(MysqlBackend)

MySQL/MariaDB via sqlx.

Postgres(PostgresBackend)

PostgreSQL via sqlx.

Sqlite(SqliteBackend)

SQLite via sqlx.

Implementations

impl Backend

pub async fn tool_list_databases(&self) -> Result<String, AppError>

Lists all accessible databases as a JSON array.

Errors

Returns AppError if the backend query fails.

pub async fn tool_list_tables( &self, database_name: &str, ) -> Result<String, AppError>

Lists all tables in a database as a JSON array.

Errors

Returns AppError if the identifier is invalid or the backend query fails.

pub async fn tool_get_table_schema( &self, database_name: &str, table_name: &str, ) -> Result<String, AppError>

Returns column definitions for a table as JSON.

Errors

Returns AppError if identifiers are invalid or the backend query fails.

pub async fn tool_get_table_schema_with_relations( &self, database_name: &str, table_name: &str, ) -> Result<String, AppError>

Returns column definitions with foreign key relationships.

Errors

Returns AppError if identifiers are invalid or the backend query fails.

pub async fn tool_execute_sql( &self, sql_query: &str, database_name: &str, ) -> Result<String, AppError>

Executes a SQL query and returns results as a JSON string.

Includes read-only validation as defence-in-depth. The read_query tool handler also validates, but this ensures safety even when calling tool_execute_sql directly (e.g. from integration tests).

Errors

Returns AppError if the query is blocked by read-only mode or the backend query fails.

pub async fn tool_create_database( &self, database_name: &str, ) -> Result<String, AppError>

Creates a database if it does not already exist.

Errors

Returns AppError if the identifier is invalid, the server is in read-only mode, or the backend query fails.

Trait Implementations

impl Clone for Backend

fn clone(&self) -> Backend

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl DatabaseBackend for Backend

async fn list_databases(&self) -> Result<Vec<String>, AppError>

Lists all accessible databases.

async fn list_tables(&self, database: &str) -> Result<Vec<String>, AppError>

Lists all tables in a database.

async fn get_table_schema( &self, database: &str, table: &str, ) -> Result<Value, AppError>

Returns column definitions for a table.

async fn get_table_schema_with_relations( &self, database: &str, table: &str, ) -> Result<Value, AppError>

Returns column definitions with foreign key relationships.

async fn execute_query( &self, sql: &str, database: Option<&str>, ) -> Result<Value, AppError>

Executes a SQL query and returns rows as a JSON array.

async fn create_database(&self, name: &str) -> Result<Value, AppError>

Creates a database if it doesn’t exist.

fn dialect(&self) -> Box<dyn Dialect>

Returns the SQL dialect for this backend.

fn read_only(&self) -> bool

Whether read-only mode is enabled.

impl Debug for Backend

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

Formats the value using the given formatter.