Documentation Index Fetch the complete documentation index at: https://docs.prefect.io/llms.txt
Use this file to discover all available pages before exploring further.
prefect.server.utilities.databaseUtilities for interacting with Prefect REST API database and ORM layer.
Prefect supports both SQLite and Postgres. Many of these utilities
allow the Prefect REST API to seamlessly switch between the two.
Functions db_injector db_injector(func: Union[_DBMethod[T, P, R], _DBFunction[P, R]]) -> Union[_Method[T, P, R], _Function[P, R]]
generate_uuid_postgresql generate_uuid_postgresql(element: GenerateUUID, compiler: SQLCompiler, ** kwargs: Any) -> str
Generates a random UUID in Postgres; requires the pgcrypto extension.
generate_uuid_sqlite generate_uuid_sqlite(element: GenerateUUID, compiler: SQLCompiler, ** kwargs: Any) -> str
Generates a random UUID in other databases (SQLite) by concatenating
bytes in a way that approximates a UUID hex representation. This is
sufficient for our purposes of having a random client-generated ID
that is compatible with a UUID spec.
bindparams_from_clause bindparams_from_clause(query: sa.ClauseElement) -> dict[ str , sa.BindParameter[Any]]
Retrieve all non-anonymous bind parameters defined in a SQL clause
datetime_or_interval_add_postgresql datetime_or_interval_add_postgresql(element: Union[date_add, interval_add, date_diff], compiler: SQLCompiler, ** kwargs: Any) -> str
date_diff_seconds_postgresql date_diff_seconds_postgresql(element: date_diff_seconds, compiler: SQLCompiler, ** kwargs: Any) -> str
current_timestamp_sqlite current_timestamp_sqlite(element: functions.now, compiler: SQLCompiler, ** kwargs: Any) -> str
Generates the current timestamp for SQLite
date_add_sqlite date_add_sqlite(element: date_add, compiler: SQLCompiler, ** kwargs: Any) -> str
interval_add_sqlite interval_add_sqlite(element: interval_add, compiler: SQLCompiler, ** kwargs: Any) -> str
date_diff_sqlite date_diff_sqlite(element: date_diff, compiler: SQLCompiler, ** kwargs: Any) -> str
date_diff_seconds_sqlite date_diff_seconds_sqlite(element: date_diff_seconds, compiler: SQLCompiler, ** kwargs: Any) -> str
sqlite_json_operators sqlite_json_operators(element: sa.BinaryExpression[Any], compiler: SQLCompiler, override_operator: Optional[OperatorType] = None , ** kwargs: Any) -> str
Intercept the PostgreSQL-only JSON / JSONB operators and translate them to SQLite
sqlite_greatest_as_max sqlite_greatest_as_max(element: greatest[Any], compiler: SQLCompiler, ** kwargs: Any) -> str
sqlite_least_as_min sqlite_least_as_min(element: least[Any], compiler: SQLCompiler, ** kwargs: Any) -> str
get_dialect get_dialect(obj: Union[ str , Session, sa.Engine]) -> type[sa.Dialect]
Get the dialect of a session, engine, or connection url.
Primary use case is figuring out whether the Prefect REST API is communicating with
SQLite or Postgres.
Classes GenerateUUID Platform-independent UUID default generator.
Note the actual functionality for this class is specified in the
compiles-decorated functions below
Timestamp TypeDecorator that ensures that timestamps have a timezone.
For SQLite, all timestamps are converted to UTC (since they are stored
as naive timestamps without timezones) and recovered as UTC.
Methods: load_dialect_impl load_dialect_impl( self , dialect: sa.Dialect) -> TypeEngine[Any]
process_bind_param process_bind_param( self , value: Optional[datetime.datetime], dialect: sa.Dialect) -> Optional[datetime.datetime]
process_result_value process_result_value( self , value: Optional[datetime.datetime], dialect: sa.Dialect) -> Optional[datetime.datetime]
UUID Platform-independent UUID type.
Uses PostgreSQL’s UUID type, otherwise uses
CHAR(36), storing as stringified hex values with
hyphens.
Methods: load_dialect_impl load_dialect_impl( self , dialect: sa.Dialect) -> TypeEngine[Any]
process_bind_param process_bind_param( self , value: Optional[Union[ str , uuid. UUID ]], dialect: sa.Dialect) -> Optional[ str ]
process_result_value process_result_value( self , value: Optional[Union[ str , uuid. UUID ]], dialect: sa.Dialect) -> Optional[uuid. UUID ]
JSON JSON type that returns SQLAlchemy’s dialect-specific JSON types, where
possible. Uses generic JSON otherwise.
The “base” type is postgresql.JSONB to expose useful methods prior
to SQL compilation
Methods: load_dialect_impl load_dialect_impl( self , dialect: sa.Dialect) -> TypeEngine[Any]
process_bind_param process_bind_param( self , value: Optional[Any], dialect: sa.Dialect) -> Optional[Any]
Prepares the given value to be used as a JSON field in a parameter binding
Pydantic A pydantic type that converts inserted parameters to
json and converts read values to the pydantic type.
Methods: process_bind_param process_bind_param( self , value: Optional[T], dialect: sa.Dialect) -> Optional[ str ]
process_result_value process_result_value( self , value: Optional[Any], dialect: sa.Dialect) -> Optional[T]
date_add Platform-independent way to add a timestamp and an interval
interval_add Platform-independent way to add two intervals.
date_diff Platform-independent difference of two timestamps. Computes d1 - d2.
date_diff_seconds Platform-independent calculation of the number of seconds between two timestamps or from ‘now’
greatest least 
