Handling Short Records with Missing Data

When the control file definition specifies more fields for a record than are present in the record, SQL*Loader must determine whether the remaining (specified) columns should be considered null or whether an error should be generated.

If the control file definition explicitly states that a field's starting position is beyond the end of the logical record, then SQL*Loader always defines the field as null. If a field is defined with a relative position (such as dname and loc in the following example), and the record ends before the field is found, then SQL*Loader could either treat the field as null or generate an error. SQL*Loader uses the presence or absence of the TRAILING NULLCOLS clause (shown in the following syntax diagram) to determine the course of action.

Description of the illustration into_table6.eps

Description of the illustration into_table7.eps

TRAILING NULLCOLS Clause

The TRAILING NULLCOLS clause tells SQL*Loader to treat any relatively positioned columns that are not present in the record as null columns.

For example, consider the following data:

10 Accounting

Assume that the preceding data is read with the following control file and the record ends after dname:

INTO TABLE dept 
    TRAILING NULLCOLS 
( deptno CHAR TERMINATED BY " ", 
  dname  CHAR TERMINATED BY WHITESPACE, 
  loc    CHAR TERMINATED BY WHITESPACE 
)

In this case, the remaining loc field is set to null. Without the TRAILING NULLCOLS clause, an error would be generated due to missing data.