The process interface to data access. All data outside the active process' environment is managed by these processes. That includes data on the hard drive, data in databases and data intentionally shared with other processes in the active environment.
A set of processes providing access to any external data -
entities
define the context for viewing the data.
They provide access to categorized collections of instances of data.
Commonly used terms for entities are tables or files.
attributes
define which aspects of the entity are to be accessed
They provide access to field values derived from instances.
A commonly used term for attributes is fields.
instance names
define which member of the entity is to be accessed
access to specific instances
Common terms for instance names are rowids or keys.
instances
are the individual members of the entity
an instance is the container of all the values of one member of an entity.
Common terms for this are rows or records.
Data = Get Data(Entity Name, Attribute Names, Instance Name, Instance)
For a given Instance Name within the Entity, gets the Instance and extracts the values for each Attribute.
Gets the Instance from storage, unless it has been supplied by the caller in the Instance argument.
Derives the Attributes from the Instance.
Converts the attributes into format appropriate to the application system.
Returns the Attributes in Data
Returned Instance Name = Save Data(Entity Name, Attribute Names, Instance Name, Attribute Values, Instance)
For a given Instance Name within the Entity, updates the values for each Attribute and saves the Instance.
If the Instance has not been supplied, gets the Instance from storage.
Converts the Attributes into format appropriate to the database.
Updates the Attributes in the Instance.
Saves the Instance into storage, naming it Instance Name.
If the Instance Name was not specified, a new Instance Name is generated.
Returns the Instance Name
For a given Instance Name within the Entity, updates the Instance with the Attribute Values for each Attribute.
If the Instance has not been supplied, gets the Instance from storage.
Converts the Attributes into format appropriate to the database.
Updates the Attributes in the Instance.
Returns the Instance.
Success = Delete Data(Entity Name, Attribute Names, Instance Name)
Selected Data = Select Data(Entity Name, Selection Criteria, Restricting Instance Names, Attribute Names)
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