The cyclic redundancy check (CRC) value for
either an r-code file, or a database table corresponding to a buffer
object.
Data type: INTEGER
Access: Read-only
Applies
to:
Buffer object handle, RCODE-INFO handle
When applied to the RCODE-INFO system handle, the r-code CRC is calculated during
compilation and stored in the r-code file using the contents of the source files, including
included files.
When applied to the Buffer object handle,
the database CRC is calculated using the metaschema _CRC field value
from the _File record for the database record corresponding to the
buffer object's table (which can be a standard or temp-table).
The
CRC for a temp-table is calculated differently than for a standard
table. Some differences include:
- Standard tables have
a _File record in the database that contains a _CRC field for the
CRC value, which is calculated as you make changes to the table.
Temp-tables do not have a _File record, and do not exist in a database.
- The CRC values for both standard and temp-tables include the
data type, extent and position of each column in the table, as well
as index information. However, the CRC value for a standard table
includes additional information that a CRC value for a temp-table
does not (such as, the _Order field in the _File record).
- The CRC value for a standard table is stored in a .r file. The
AVM uses that CRC value at run time to verify the integrity of application
r-code that uses the table. The AVM uses the CRC value for a temp-table
to compare table parameters between a calling and called procedure
(to avoid a field-by-field comparison).
For more information
on CRCs, see OpenEdge Deployment: Managing ABL Applications.
