1.14 COPY : Specifying Load Metadata

COPY : Specifying Load Metadata

In addition to choosing a parser option, COPY supports other options to determine how to handle raw data.

These options are considered load metadata, and we can specify metadata options in different parts of the COPY statement.

Following are the places where we can specify the load metadata:

1. As a Column or Expression.

2. As a Column Option.

3. As a FROM level Option.

Following table shows Which option can be specified at what level.

Metadata Option	As a Column or Expression Option	As a  COLUMN OPTION	As a FROM  Level Option
DELIMITER	Y	Y	Y
ENCLOSED BY	Y	Y	Y
ESCAPE AS	Y	Y	Y
NULL	Y	Y	Y
TRIM	Y		Y
RECORD TERMINATOR			Y
SKIP			Y
SKIP BYTES			Y (Fixed-width only)
TRAILING NULLCOLS			Y

Notice that the NULL, ESCAPE,ENCLOSED and DELIMITER (NEED) metadata options can be specified at all the 3 levels.

The following precedence rules apply to all data loads:

• All column-level parameters override statement-level parameters.

• COPY uses the statement-level parameter if you do not specify a column-level parameter.

• COPY uses the default metadata values for the DELIMITER, ENCLOSED BY, ESCAPE AS, and NULL options if you do not specify them at either the statement- or column-level.