Understanding the AppConn Object Model

The Host Integrator COM connector connects to the Host Integrator Server and implements four main interfaces. The AppConnSessionEx object implements these interfaces. Each of the following interfaces contains methods accessible from any programming environment that supports COM:

AppConnModel interface— Use model-level methods to access host data from the host application model. To use model level methods, you must have knowledge of the Design Tool's modeling process, though an intimate knowledge of the host application is not required.
AppConnChannel interface —The AppConn COM channel interface contains methods for connecting to and obtaining information about sessions and models running on Verastream Host Integrator Servers.
AppConnTable interface —Use table/procedure methods to access table definitions of data created during the Design Tool's modeling process and stored in the host application model. Using the methods in this interface requires no knowledge of the host application or the modeling process.
AppConnTerm interface — Use terminal methods to access data directly from the host. Unlike model-level methods, using terminal methods requires an intimate knowledge of the host application since the entity definitions created in the model file are not used with terminal level methods.

See the Accessing host data section of Using Host Integrator Connector APIs for more information on these interfaces.

Each of the main interfaces implements certain objects differently and may include additional objects derived from one of the basic objects. The following list describes each basic object and provides links to the corresponding sections of the Visual Basic Reference.

Object

Description

AppConnRecord

Visual Basic methods

Provides storage for a collection of elements returned from the Host Integrator Server. It may also contain an index number and terminal attributes collection for data returned from the model interface (for example, FetchRecords and GetAttributes).

Note: The element collections are read-only.

AppConnModelRecord

Visual Basic methods

A record that also implements index number and terminal attributes accessor functions using a derived class.

Note: The index number and terminal attributes collections are read-only.

AppConnRecordSet

Visual Basic methods

Provides storage for a collection of records and metadata for the elements of the records returned from Host Integrator Server.

Notes:

Record and metadata collections are read-only.
Empty recordsets can be created and filled in by the FromXMLString method.
Once you execute an insert on a recordset, you need to reset the recordset by either navigating away from it and returning, or executing the home operation on the recordset before executing any other method on it.

AppConnStringList

Visual Basic methods

Provides dynamic storage for a list of strings that can be used to send data to, and retrieve data from, an AppConn session.

AppConnStringMap

Visual Basic methods

Provides dynamic storage for a keyed map of strings that can be used to send data to or retrieve data from, an AppConn session. You can also get data from a record.

AttributeMetaData

Visual Basic interface

Contains the metadata defined in the model for an entity attribute. The following are examples of attribute metadata:

name
description
length
readable flag
writeable flag
read variable
write variable
terminal attribute enabled flag

Note: This object is read only.

ColumnMetaData

Visual Basic methods

Contains the metadata defined in the model for a table column. The following are examples of column metadata:

name
description
column type
min
max
key flag

Note: This object is read only.

FieldMetaData

Visual Basic methods

Contains the metadata defined in the model for a recordset field. The following are examples of field metadata:

name
description
column
length
readable flag
writeable flag
key flag
terminal attributes enabled flag.

Note: This object is read only.

OperationMetaData

Visual Basic methods

Contains the metadata defined in the model for an operation. The following are examples of operation metadata:

name
description
destination
alternate destinations
attributes used in the operation
variables used in the operation
operation timeout
default operation flag

Note: This object is read only.

ProcedureMetaData

Visual Basic methods

Contains the metadata defined in the model for a procedure. The following are examples of procedure metadata:

name
description
procedure type
used for SQL flag
input columns
output columns
filter columns
required input
required filter columns

Note: This object is read-only.

RecordSetMetaData

Visual Basic methods

Contains the metadata defined in the model for a recordset. The following are examples of recordset metadata:

name
description
insert flag
select flag
scroll movements

Note: This object is read-only.

TerminalAttributes

Visual Basic methods

Contains the screen attributes on the host terminal for an attribute or field. The following are examples of screen attributes:

blinking flag
reverse flag
underscore flag
half brite flag
protected flag
numeric flag
nondisplay flag
column separated flag
pen detect flag
intense flag
color value

Note: This object is read-only.

VariableMetaData

Visual Basic methods

Contains the metadata defined in the model for a model variable. The following are examples of variable metadata:

name
description
default value
initialization type
variable type
hidden flag
readable flag
writeable flag
encrypted flag

Note: This object is read-only.

ElementLocation

Visual Basic methods

Contains the location information for the element. The following are examples of element location:

name
element type
top row
left column
number of rows
number of columns
offset
length
region type

Note: This object is read-only.

ElementLocationList

Visual Basic methods

Provides storage for a list of element locations.

Note: This object is read-only.

TerminalField

Visual Basic methods

Contains the location information for the element. The following are examples of element location:

top row
left column
offset
length
terminal attributes

Note: This object is read-only.

StringMapSet

Visual Basic methods

Provides dynamic storage for a list of string maps that can be used to send data to an AppConn session.