This topic discusses the migration packet API.

  • All migration packets must be derived from the BasePacket class for the framework to execute them.
    • There are several specialized subclasses which facilitate certain types of migration

Classes

BasePacket

Methods

FunctionParametersReturn ValueDescription
BasePacket.__init__(self, migrationrule=None)migrationrule: UUID
Initializes a new packet. If a packet is instanced without a uuid, not all features might work
BasePacket.create_migrationrule(self, override_dict=None)override_dict: A dictionary of attributes to pass to ppms.create_recordThe newly created UUIDCreates a record in table 314 for this migration packet and update the internal state of this instance so that further calls like save_history work
BasePacket.delete(self)

Deletes this migration packet and all history records
BasePacket.delete_log_content(self)

Deletes the currently buffered log and reset the internal logging buffer. This will not delete any logs saved to the database.
BasePacket.fail(self, reason='')reason: A text that describes why the packet failed
Updates the internal state of the packet to mark it as failed.

Please note that this does not stop the execution of this migration packet and should always be used with a return
BasePacket.fix(self, packet_runner)packet_runner: The instance of the migration framework that is running this packet
This method is called by the framework and should contain the code which this packet is supposed to run to migrate the system
BasePacket.generate_logfile_name(self)
A name that can be used as a logfile nameGenerates a logfile name from the parameters of the packet
BasePacket.get_dependencies(self)
A list of dependenciesThis method is called by the framework and should return the dependencies of this packet
BasePacket.log(self, text)text: Log message
Log a message
BasePacket.log_heading(self, text, level=0)text: Log message

level: A number between 0 and 4

Writes a heading in the log. Headings are marked by stars around the text. A value of 0 puts 5 stars around the text, a value of 4 puts 1 star around the text
BasePacket.make_active(self)

Called by the framework before execution to initialize the packet logging correctly
BasePacket.mark_as_done(self)

Sets the Completed flag to True
BasePacket.mark_as_undone(self)

Sets the Completed flag to False
BasePacket.pending(self)

Sets the packet state to pending.

Please note that this does not stop the execution of this migration packet and should always be used with a return
BasePacket.rollback(self)

This method is called by the framework when a packet fails, so that it can gracefully undo any incomplete changes made to the system. The default implementation simply logs that no rollback action was defined
BasePacket.save_history(self)
True or FalseCreates a new history record in table 315 based on the current execution. The content of the log is written into a hyperlink and the current internal state is saved to Status
BasePacket.skip(self, reason='')reason: A text that describes why this packet was skipped
Deprecated
BasePacket.success(self)

This method must be called after a packet has migrated the system successfully.

Please note that this does not stop the execution of this migration packet and should always be used with a return
BasePacket.unnecessary(self)

Marks the packet as unnecessary for the current migration.

Please note that this does not stop the execution of this migration packet and should always be used with a return

Classmethods

FunctionParametersReturn ValueDescription
BasePacket.from_packet_path(cls, packet_path)packet_path: Python pathThe packet instance or NoneSearch for the migration packet class, initialize it, and set the uuid accordingly

Properties

PropertyGetterSetterDescription
BasePacket.__fpath__Returns the path that is saved to Python path
BasePacket.__name__The name of the packet class
BasePacket.componentFetches the component of the package that contains the migration packet
BasePacket.customizing_dependencies_are_metReturns wheter the MinVersionDependency and MaxVersionDependency dependencies attached to this packet are met
BasePacket.dbms_dependency_is_metReturns wheter the DBMSDependency attached to this packet is met
BasePacket.dependenciesReturns all dependencies of this packet as an iterable oject
BasePacket.dependencies_are_metReturns whether all dependencies are met
BasePacket.description_longReturns the entire docstring
BasePacket.description_shortReturns the first sentence of the docstring
BasePacket.doneReturns and sets to Completed. Note that setting the flag will write log messages to the packets internal logging buffer
BasePacket.is_failed_or_still_openReturns if the last_state is one of PacketState.PENDING, PacketState.SKIPPED or PacketState.FAILED
BasePacket.last_stateReturns the PacketState of the last execution. If the packet has never been executed, PacketState.NEW is returned
BasePacket.log_contentReturns the content of the internal logging buffer
BasePacket.logfile_suffixThe file ending for the logfile hyperlink
BasePacket.maximum_customizing_dependencyReturns the expected version of a MaxVersionDependency attached to this packet or an empty string
BasePacket.maximum_customizing_dependency_is_metReturns whether the MaxVersionDependency is met
BasePacket.migrationruleUUID
BasePacket.minimum_customizing_dependencyReturns the expected version of a MinVersionDependency attached to this packet or an empty string
BasePacket.minimum_customizing_dependency_is_metReturns wheter the MinVersionDependency is met
BasePacket.packet_dependencies_are_metReturns whether all PacketDependency instances are met
BasePacket.pythonpathPython path
BasePacket.releaseGets the release from the package this migration packet is part of
BasePacket.release_versionrelease converted to a LooseVersion
BasePacket.twiki_urlReturns the url to the ReleaseNotes topic where this packet is described

SucceedOldPacket

SucceedOldPacket provides a method for easily setting the Erledigt flag on other packets.

  • It is used to mark packets which are superseded by a more recent packet as done, regardless of whether they succeeded before or not

Methods

FunctionParametersReturn ValueDescription
SucceedOldPacket.mark_packet_as_done(self, packet_path)packet_path: The Python path of a packetTrueMarks the packet with the specified Python path as done. If no packet with that path exists, no error will be raised

ChangeDTPPacket

ChangeDTPPacket provides methods for changing values on dtp level

  • All methods log intensively to assist with debugging

Methods


FunctionParametersReturn ValueDescription
ChangeDTPPacket.change_value(self, record, attribute, old_value, new_value)record: A DtpRecord instance
attribute: The python id of the attribute to change
old_value: The value you expect the data item to have
new_value: The value the data item should be set to
True or FalseChanges a value on a data item if the system matches the expected state. This method returns True if the value was changed successfully or if the data item already has the desired new_value. False is returned when the old_value does not match or if the data item could not be changed. If you pass None as old_value, no check will be performed.
ChangeDTPPacket.get_record(self, dt_num, key_list, di_list)dt_num: DT
key_list: List of keys
di_list: List of data items
DtpRecord or NoneA wrapper around ppms.search_record that logs to the migration packet
ChangeDTPPacket.verify_value(self, record, attribute, value)record: DtpRecord
attribute: Python id of the attribute to check
value: The expected value
True or FalseVerifies that a dataitem matches a certain ex

SQLPacket

The SQLPacket is designed to execute sql files and make changes to the database

  • select_and_log() and modify_and_log() should be used over calling db_select() and db_modify() directly, as the SQLPacket methods provide useful logging

Methods

FunctionParametersReturn ValueDescription
SQLPacket.apply_dml_file(self, sql_dialect, filename, split=True, separator=;$)sql_dialect: 'dbms' or 'ansi'
filename: Filename

split: True or False
separator: A regular expression to determine how to split the statements in the file

Applies an sql file from the current folder to the database. The sql files should have a suffix like _oracle, _mssql or _ansi but this method must be called without the suffix. Based on the sql_dialect parameter, the correct suffix is added and the file is parsed. When split is True, the separator is used to split the file content and then all statements are executed.

Autocommit is disabled and then all statements are executed before committing to the database. If an error is encountered in the course of this, db_rollback() will be called.
SQLPacket.apply_fix_ddl_file(self, sql_dialect, filename, split=False, separator=;$)sql_dialect: 'dbms' or 'ansi'
filename: Filename

split: True or False
separator: A regular expression to determine how to split the statements in the file

Works like apply_dml_file, except that the autocommit state is not changed
SQLPacket.get_queries_from_file(self, file_path, encoding=utf-8, split=True, separator=;$)file_path: The path to a file containing SQL statements

encoding: The encoding of the file
split: True or False
separator: A regular expression to determine how to split the statements in the file
A list of statementsReads the file at the given path and extract the queries. When split is False, a list with only 1 statement is returned
SQLPacket.get_sql_file_path(self, sql_dialect, filename)sql_dialect: 'dbms' or 'ansi'
filename: Filename
Filename with added suffixReturns the path to the given file name with an added suffix
SQLPacket.select_and_log(self, query, log_rows=True)query: A select statement

log_rows: True or False
Result of the selectLogs and executes a select. When log_rows is True, the number of rows selected is also logged

Staticmethods

FunctionParametersReturn ValueDescription
SQLPacket.alter_precision_of_numeric_column(table_name, column_name, desired_precision, expected_precision=None)table_name: Variable name
column_name: SQL-ID
desired_precision: The precision the column should have

expected_precision: The precision the column currently has
True or FalseAlters the precision of a numeric column. When expected_precision is given and does not match, nothing will be changed.
SQLPacket.column_allows_null(table_name, column_name)table_name: Variable name
column_name: SQL-ID
True or FalseChecks whether a column allows Null values
SQLPacket.column_exists(table_name, column_name)table_name: Variable name
column_name: SQL-ID
True or FalseChecks whether a column exists
SQLPacket.columns_have_index_already(table_name, column_names)table_name: Variable name
column_names: List of SQL-ID
True or FalseChecks whether a bunch of columns have an index spanning across them
SQLPacket.constraint_exists(table_name, constraint_name)table_name: Variable name
constraint_name: Name of the constraint
True or FalseChecks whether a constraint exists
SQLPacket.drop_column(table_name, column_name, remove_customizing=False)table_name: Variable name
column_name: SQL-ID

remove_customizing: True or False

Drops a column. Returns True if the column was dropped or does not exist.
When remove_customizing is True, the data item that was associated with this table/column pair is identified and removed from all customizing tables. This includes data fields, exits, sub data items and the data item itself.
SQLPacket.drop_constraint(table_name, constraint_name)table_name: Variable name
constraint_name: Name of the constraint

Drops a constraint if it exists
SQLPacket.drop_index(table_name, index_name)table_name: Variable name
index_name: Name of the index

Drops a index if it exists
SQLPacket.get_char_length_of_varchar_column(table_name, column_name)table_name: Variable name
column_name: SQL-ID
Maximum number of charactersGets the maximum number of characters for a varchar column.
SQLPacket.get_column_type(table_name, column_name)table_name: Variable name
column_name: SQL-ID
A column type like 'NUMERIC' or 'NUMBER'Gets the column type of the given column in upper case
SQLPacket.get_constraints_of_column(table_name, column_name)table_name: Variable name
column_name: SQL-ID
List of constraint namesGets the constraints of the column
SQLPacket.get_default_value_for_column(table_name, column_name)table_name: Variable name
column_name: SQL-ID
Default value or NoneGets the default value of a column. Returns None if the table/column does not exist.

This is currently only implemented for Oracle!
SQLPacket.get_indices_of_column(table_name, column_name)table_name: Variable name
column_name: SQL-ID
List of index namesGets the indices this column is used in
SQLPacket.get_precision_and_scale_of_column(table_name, column_name)table_name: Variable name
column_name: SQL-ID
Tuple of (precision, scale)Gets the column precision and scale if applicable
SQLPacket.get_varchar_column_type(table_name, column_name)table_name: Variable name
column_name: SQL-ID
'B' or 'C'Gets the varchar column type. Returns B for bytes and C for char.

This is currently only implemented for Oracle!
SQLPacket.index_exists(table_name, index_name)table_name: Variable name
index_name: SQL name
True or FalseChecks whether a given index exists
SQLPacket.is_nullable(table_name, column_name)table_name: Variable name
column_name: SQL-ID
True or FalseChecks whether a column allows null values. Returns None if the table/column pair does not exist
SQLPacket.modify_and_log(query, log_rows=True)query: Sql statement

log_rows: True or False
Number of rows affectedExecutes an sql statement on the database. If log_rows is True then the number of rows modified is logged.
SQLPacket.move_table_to_different_schema(table_number, source_schema, target_schema)table_number: DT
source_schema: DB-Schema
target_schema: DB-Schema
TrueMoves a table to a different schema. If the table has hyperlinks, this will raise a NotImplementedError. Translations will be ported automatically, but the method was written to only support Q5B as a target schema for now. If the table has no translations, the schema will not be changed.
SQLPacket.object_is_materialized_view(object_name)object_name: SQL nameTrue or FalseChecks whether a materialized view with the given name exists. Note that materialized views do not exist in MSSQL.
SQLPacket.object_is_table(object_name)object_name: SQL nameTrue or FalseChecks whether a table with the given object name exists
SQLPacket.procedure_exists(procedure_name)procedure_name: SQL nameTrue or FalseChecks whether a given procedure exists.

This is currently only implemented for MSSQL!
SQLPacket.remove_constraints_from_column(table_name, column_name)table_name: Variable name
column_name: SQL-ID

Removes all constraints from the column
SQLPacket.remove_customizing_for_column(table_name, column_name)table_name: Variable name
column_name: SQL-ID
True or FalseRemoves all customizing records that use the dataitem associated with the table/column pair.
SQLPacket.table_exists(table_name)table_name: Variable nameTrue or FalseChecks whether a table with the given object name exists
SQLPacket.rename_table(old_table_name, new_table_name)old_table_name: Variable name
new_table_name: New table name
True or FalseRenames a table on the database.
SQLPacket.rename_column(table_name, old_column_name, new_column_name)table_name: Variable name
old_column_name: SQL-ID
new_column_name: New column name
True or FalseRenames a column in a table.