migration - Dependencies

This topic discusses the dependency API provided by the migration framework.

A migration packet can have dependencies that are evaluated during migration to determine wheter the packet should run or not
When the dependencies are not met, the packet is marked as pending
- The MinVersion and MaxVersion dependencies as well as the DBMSDependency will mark a packet as unnecessary instead

Classes

The base class.

Function	Parameters	Description
BaseDependency.__init__`(self)`		Initializes the dependency
BaseDependency.get_log_content`(self)`		Retrieves a list of all log statements in the buffer and clears it
BaseDependency.log`(self, text)`	text: String	Writes into the internal log buffer

Property	Getter	Setter	Description
BaseDependency.is_met			This property is abstract and must be implemented in a subclass. It must be returned if the condition of the dependency is satisfied

Dependency on the type of database used.

Function	Parameters	Return Value	Description
DBMSDependency.__init__`(self, expected_dbms)`	expected_dbms: `'000002'` for Oracle and `'000004'` for MSSQL		Initializes the dependency

Will check whether the value in database changeset is greater or equal to the version this dependency was initialized with

Function	Parameters	Return Value	Description
MaxVersionDependency.__init__`(self, version)`	version: Customizing version like `'39.5.11'`		Initializes the dependency

Will check whether the value in database changeset is less or equal to the version this dependency was initialized with

Function	Parameters	Return Value	Description
MinVersionDependency.__init__`(self, version)`	version: Customizing version like `'39.5.11'`		Initializes the dependency

Function	Parameters	Return Value	Description
PacketDependency.__init__`(self, packet_path, expected_state)`	packet_path: Python path expected_state: PacketState		Initializes the dependency