Trait MetadataExecutor 

pub trait MetadataExecutor {
    type Row;

    // Required methods
    fn query_one(
        &mut self,
        operation: &'static str,
        statement: &str,
        params: MetadataParameters<'_>,
    ) -> Result<Self::Row, PgMetaError>;
    fn query_optional(
        &mut self,
        operation: &'static str,
        statement: &str,
        params: MetadataParameters<'_>,
    ) -> Result<Option<Self::Row>, PgMetaError>;
    fn query_many(
        &mut self,
        operation: &'static str,
        statement: &str,
        params: MetadataParameters<'_>,
    ) -> Result<Vec<Self::Row>, PgMetaError>;
    fn execute_command(
        &mut self,
        operation: &'static str,
        statement: &str,
        params: MetadataParameters<'_>,
    ) -> Result<u64, PgMetaError>;
    fn with_transaction<T>(
        &mut self,
        operation: &'static str,
        f: impl FnOnce(&mut dyn MetadataTransaction<Row = Self::Row>) -> Result<T, PgMetaError>,
    ) -> Result<T, PgMetaError>;
}

Session-scoped metadata execution interface.

Required Associated Types

type Row

Row representation returned by the concrete executor.

Required Methods

fn query_one( &mut self, operation: &'static str, statement: &str, params: MetadataParameters<'_>, ) -> Result<Self::Row, PgMetaError>

Runs a query expected to return exactly one row.

Errors

Returns an error when PostgreSQL/libpq rejects the query or the result shape does not match the executor contract.

fn query_optional( &mut self, operation: &'static str, statement: &str, params: MetadataParameters<'_>, ) -> Result<Option<Self::Row>, PgMetaError>

Runs a query expected to return zero or one row.

Errors

Returns an error when PostgreSQL/libpq rejects the query or the result shape contains more than one row.

fn query_many( &mut self, operation: &'static str, statement: &str, params: MetadataParameters<'_>, ) -> Result<Vec<Self::Row>, PgMetaError>

Runs a query that can return many rows.

Errors

Returns an error when PostgreSQL/libpq rejects the query or parameters.

fn execute_command( &mut self, operation: &'static str, statement: &str, params: MetadataParameters<'_>, ) -> Result<u64, PgMetaError>

Executes a metadata write command.

Errors

Returns an error when PostgreSQL/libpq rejects the command or parameters.

fn with_transaction<T>( &mut self, operation: &'static str, f: impl FnOnce(&mut dyn MetadataTransaction<Row = Self::Row>) -> Result<T, PgMetaError>, ) -> Result<T, PgMetaError>

Runs caller-supplied work inside a metadata transaction.

Errors

Returns an error if the transaction cannot be opened or committed, or if the callback returns an error.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementations on Foreign Types

impl MetadataExecutor for LibpqOAuthConnection

type Row = LibpqOAuthRow

fn query_one( &mut self, operation: &'static str, statement: &str, params: MetadataParameters<'_>, ) -> Result<Self::Row, PgMetaError>

fn query_optional( &mut self, operation: &'static str, statement: &str, params: MetadataParameters<'_>, ) -> Result<Option<Self::Row>, PgMetaError>

fn query_many( &mut self, operation: &'static str, statement: &str, params: MetadataParameters<'_>, ) -> Result<Vec<Self::Row>, PgMetaError>

fn execute_command( &mut self, operation: &'static str, statement: &str, params: MetadataParameters<'_>, ) -> Result<u64, PgMetaError>

fn with_transaction<T>( &mut self, operation: &'static str, f: impl FnOnce(&mut dyn MetadataTransaction<Row = Self::Row>) -> Result<T, PgMetaError>, ) -> Result<T, PgMetaError>

Implementors

impl MetadataExecutor for PgMetadataConnection

type Row = Row