params

Declare the parameter block for an operation, entry, or global ProcScript.

params
   DataType ParamName                      : Direction
  {DataType} Field.Entity{.Model}       : Direction
  {DataType} $ComponentVariable$           : Direction
  {byRef} | {byVal} struct ParamName : Direction
   entity Entity{.Model}                   : Direction
   occurrence Entity{.Model}               : Direction
   xmlstream [DTD:DTDName]ParamName        : Direction
endparams

Parameters

Struct Parameters

The way that Structs are passed has implications for the way in which the data is synchronized. For more information, see Passing Struct Parameters.

Entity and Occurrence Parameters

entity and occurrence parameters are known as constructed parameters. An entity parameter transfers all occurrences of the specified entity from one component to the other component. An occurrence parameter transfers the current occurrence of the specified entity from one component to the other component.

Note:  Only fields whose Is External property is T can be included in the entity parameter or occurrence parameter. By default, this is true for DBMS entities.

On each call to the operation, an implicit creocc is performed to set aside sufficient memory for the occurrence parameter. The call does not release the memory implicitly, but the memory can be cleared by clearing the data in the component entity that was created by the call.

• If the entity parameter has direction IN or INOUT, when the operation starts, an implicit clear/e statement for that entity is performed in the component instance before the occurrences are filled with the data being transferred.
• If the entity parameter has direction OUT or INOUT, when the operation returns, an implicit clear/e statement for that entity is performed in the requesting component instance before the occurrences are filled with the data being returned. This is followed by a release/e/mod statement for the entity.
• If the occurrence parameter has direction IN or INOUT, when an operation starts, the current occurrence of the requesting component becomes the new occurrence in the requested component (such as an entity service).
• If the occurrence parameter has direction OUT or INOUT, when the operation returns, the current occurrence of the requested component becomes the new occurrence in the requesting component.

Note:  If a component is activated asynchronously (for example, with the /async switch on the newinstance statement), you should not activate an operation that contains a parameter with the direction OUT or INOUT.

XML Stream Parameters

xmlstream parameters contain XML data, which can be transferred between the parameter and the component's external data structure by ProcScript statements, using xmlsave and xmlload. For more information, see xmlsave and xmlload.

Scope of Parameters

An entity, occurrence, field, or component variable parameter is defined at the component level. The values of these parameters are component-wide in scope; that is, the values are available to all operations and modules in the component.

A named parameter exists only in the operation or module in which it is defined. Its scope is limited to that operation or module. It cannot be directly referenced from another operation or module in the component, or from a local or global ProcScript called by the operation or module. If a named parameter has the same name as a field defined in the component, the parameter takes precedence over the field; to access the field, you must use the qualified field name.

For example, consider a component that contains a field named DATE in the entity PO. The operation TODAY has a named parameter, DATE. To update the field DATE in the operation TODAY, the field must be referenced by its qualified name, including its entity:

operation TODAY
params
   date DATE : OUT
endparams
DATE = $date ;assign the current date to parameter DATE
DATE.PO = $date ;assign the current date to field DATE.PO
end ; operation TODAY

xmlstream parameters have the same scope as named parameters. However, the data in an XML stream is not accessible to Uniface until the data has been loaded into the component's external data structure, which is accessible by all ProcScript modules in the component.

struct parameters have the same scope as named parameters. Unlike other named parameters, which contain data, a struct parameter contains only a reference to a Struct. The Struct itself is unaffected by the scope of the struct parameter. Thus, when the operation or entry completes, the reference to the Struct no longer exists, but the Struct itself remains (as long as any variable refers to it).