What is the default field mapping for RDBMS?

For Oracle the mapping is hard-coded. For ODBC (and DB2), the mapping depends on what the engine finds at run time. Appx asks the backend database for a list of data types and then tries to find the closest match for each field.

For Oracle (with Appx 4.2.8):

Appx field type = Alpha or Logic

if the field is a key segment , Appx builds a CHAR(n) column


if the field is less than 6 character long, Appx builds a CHAR(n)

column,

otherwise, Appx builds a VARCHAR(n) column

Appx field type = Date

for CCYYMMDDhhmmss key segments, Appx builds a VARCHAR(14) column


for CCYYMMDDhhmmss non-key fields, Appx builds a DATE column


for all other date components,  Appx builds a VARCHAR(n) column

Appx field type = Numeric (binary)

if field length = 1, Appx builds a NUMBER( 3, 0 ) column


if field length = 2, Appx builds a NUMBER( 5, 0 ) column


if field length = 4, Appx builds a NUMBER( 10, 0 ) column

Appx field type = Numeric (packed)

Appx builds a NUMERIC( x, y ) column