many-to-many: The cardinality of a relation, where more than one instance of the first class can be related to one or more instances of the second class.
many-to-one: The cardinality of a relation, where more than one instance of the first class can be related to one instance of the second class.
margin: The distance in workspace units between the outermost items upon a workspace and the workspace's border. Each workspace's margins are automatically maintained by G2. Set the default margin for all new workspaces in the Miscellaneous Parameters system table.
memory leak: A loss of usable storage space caused by the application's failure to correctly reclaim the memory occupied by the current KB's transient items.
menu: A list of choices that G2 displays when you click the mouse on the G2 window's background or on an item. Selecting some menu choices causes G2 to display another menu, called a submenu.
Message Board: A named KB workspace that can be the destination of messages from an
metacharacters: Special characters that let you specify a wildcarded name expression. For example, the asterisk (*) matches zero or more characters.
metacolor: A symbol that indirectly assigns a color value to a color attribute of an item. There are three metacolors:
meter: A display item showing the value of an arithmetic expression as a vertical bar along a numeric scale.
meter lag time: A time interval that represents how much data G2 should average when computing values displayed by G2 meters. Set this time interval in the
Meter-lag-timeattribute of the Timing Parameters system table.
method: A specially-constructed procedure that performs a generic operation in a class-specific manner.
mixin class: An abstract extensible class that you use in conjunction with a foundation class to define subclasses via multiple inheritance. Mixin classes define sets of attributes that would not be useful alone, but can be used to customize other classes to serve particular purposes.
modularized KB: A KB is modularized as long as the
Top-level-moduleattribute of its installed Module Information system table has a value other than the symbol
unspecifiedand the KB's modules are consistently modularized. A current KB that contains more than one module also contains more than one set of system tables; the Module Information system table for each set represents one module. If the current KB is modularized, the installed Module Information system table is associated with the current KB's top-level module.
If the current KB is consistently modularized, G2 can save each module it contains (and the items associated with that module) to a distinct KB file. If the current KB is not consistently modularized, G2 can only save the current KB as a whole into one KB file. If a stored KB file is consistently modularized, it contains only one set of system tables. If a stored KB file is modularized but not consistently, it contains one set of system tables for each module that it contains.
module: An entity in a knowledge base that G2 automatically associates with a set of system tables and optionally with a set of top-level workspaces. In this set of system tables, the Module Information system table names the module. If the current KB contains modules, it is modularized.
module hierarchy: The network of directly-requires relationships among a set of modules. A module hierarchy consists of one top-level module, and optionally one or more modules that are directly required by the top-level module, modules that are directly required by those modules, and so on.
module search path: A list of directories that G2 searches to load a modularized KB file that contains a directly required module.
module-map file: An ASCII text file in which each line associates the name of a module in the current KB with either a directory pathname or a fully qualified filename. G2 uses the module-map file when you direct G2 to save a module in the current KB to its own KB file.
mouse click: The act of pressing and releasing any button on the hand-held mouse.
mouse-tracking procedure: A user-defined G2 procedure that can be invoked from a configuration statement that includes the phrase
pressing ... on ... start. The procedure exists to respond to a change in the mouse pointer's location within a particular window, until the next mouse-click event within that window.
multiple inheritance: In object-oriented programming, the practice of allowing a class to have two or more direct superior classes, and inheriting the properties of them all.
multiple inheritance class: A class that has, or inherits from any class that has, more than one direct superior class.