Syntax 1 For executing pipeline objects

Description

Executes a pipeline object, which transfers data from the
source to the destination as specified by the SQL query
in the pipeline object. This pipeline object is a property of a
user object inherited from the pipeline system object.

Controls

Pipeline objects

Syntax

<span>pipelineobject</span>.<span>Start</span> ( <span>sourcetrans</span>, <span>destinationtrans</span>, <span>errorobject</span> <br>   {, <span>arg1</span>, <span>arg2</span>,..., <span>argn</span> } )

1	<span>pipelineobject</span>.<span>Start</span> ( <span>sourcetrans</span>, <span>destinationtrans</span>, <span>errorobject</span> <br> {, <span>arg1</span>, <span>arg2</span>,..., <span>argn</span> } )

Argument	Description
pipelineobject	The name of a pipeline user object that contains the pipeline object to be executed
sourcetrans	The name of a transaction object with which to connect to the source database
destinationtrans	The name of a transaction object with which to connect to the target database
errorobject	The name of a DataWindow control or Data Store in which to store the pipeline error DataWindow
argn (optional)	One or more retrieval arguments as specified for the pipeline object in the Data Pipeline painter

Return Values

Integer. Returns 1 if it succeeds and
a negative number if an error occurs. Error values are:

-1 Pipe
open failed
-2 Too many columns
-3 Table already exists
-4 Table does not exist
-5 Missing connection
-6 Wrong arguments
-7 Column mismatch
-8 Fatal SQL error
in source
-9 Fatal SQL error
in destination
-10 Maximum number of errors exceeded
-12 Bad table syntax
-13 Key required but not supplied
-15 Pipe already in progress
-16 Error in source database
-17 Error in destination database
-18 Destination database is read-only

If any argument’s value is null, Start returns null.

Usage

A pipeline transfer involves several PowerBuilder objects.
You need:

A pipeline object,
which you define in the Data Pipeline painter. It contains the SQL statements that specify what
data is transferred and how that data is mapped from the tables
in the source database to those in the target database.
A user object inherited from the pipeline system
object. It inherits properties that let you check the progress of
the pipeline transfer. In the painter, you define instance variables
and write scripts for pipeline events.
A window that contains a DataWindow control or a
Data Store for the pipeline-error DataWindow. Do not put a DataWindow
object in the DataWindow control. The control displays PowerBuilder’s
pipeline-error DataWindow object if errors occur when the pipeline
executes.

The window can also include buttons, menus, or some other
means to execute the pipeline, repair errors, and cancel the execution.
The scripts for these actions use the functions Start, Repair,
and Cancel.

Before the application executes the pipeline, it needs to
connect to the source and destination databases, create an instance
of the user object, and assign the pipeline object to the user object’s
DataObject property. Then it can call Start to
execute the pipeline. This code may be in one or several scripts.

When you execute the pipeline, the piped data is committed
according to the settings you make in the Data Pipeline painter.
You can specify that:

The
data is committed when the pipeline finishes. If the maximum error limit
is exceeded, all data is rolled back.
Data is committed at regular intervals, after a
specified number of rows have been transferred. When the maximum
error limit is exceeded, all rows already transferred are committed.

For information about specifying the pipeline
object in the Data Pipeline painter and how the settings affect
committing, see the PowerBuilder Users Guide.
For more information on using a pipeline in an application, see Application
Techniques.

When you dynamically assign the pipeline object to the user
object’s DataObject property, you must remember to include
the pipeline object in a dynamic library when you build your application’s
executable.

Examples

The following script creates an instance of the pipeline
user object, assigns a pipeline object to the pipeline user object’s
DataObject property, and executes the pipeline. I_src and i_dst are
transaction objects that have been previously declared and created.
Another script has established the database connections.

U_pipe is the user object inherited
from the pipeline system object. I_upipe is an
instance variable of type u_pipe. P_pipe is
a pipeline object created in the Data Pipeline painter:

i_upipe = CREATE u_pipe

1	i_upipe = CREATE u_pipe

i_upipe.DataObject = "p_pipe"

1	i_upipe.DataObject = "p_pipe"

i_upipe.<span>Start</span>(i_src, i_dst, dw_1)

1	i_upipe.<span>Start</span>(i_src, i_dst, dw_1)

Syntax 1 For executing pipeline objects – PB Docs 126