alter()

Read(25) Label: table sequence, alter, field,

Description:

The function alters fields in a table sequence.

Syntax:

T.alter(Fi,…;F’i,…)

Note:

The function modifies fields of table sequence T according to the specified order Fi,…, and arranges the other fields in their original order. Add parameter Fi as a new field if there isn’t such a field in the table sequence; parameter F’I is the field to be deleted.

Parameters:

T

A table sequence

Fi

Field name

F’i

Field name

Return value:

A table sequence

Example:

 

A

 

1

=demo.query("select class,studentid,subject,score from scores")

The scores table contains columns as follows:

2

=A1.alter(classname;CLASS)

Add a new field classname to A1’s table sequence and deletes CLASS field

3

=A2.alter(classname,STUDENTID,gender)

Add a new field gender to A2’s table sequence according to the specied position and arrange the rest of the fields after the specific ones in their original order

4

=A3.alter(;gender,classname)

Delete gender field and classname field