T .keys()

Read(368) Label: table sequence, set a key,

Description:

Set a key for a table sequence.

Syntax:

T.keys(Ki,…)

Note:

The function sets Ki,… as the key of the table sequence T. The absence of the parameter will clear the key. A T.create() operation will copy the key at the same time.

Parameters:

T

A table sequence

Ki

Key name

Options:

@t(…,KT)

Set the last parameter KT as the time key, and make all other parameters the basic keys

Return value:

A table sequence with a key

Example:

 

A

 

1

=demo.query("select EID,NAME,DEPT,SALARY,HIREDATE from EMPLOYEE order by EID asc,DEPT asc")

 

2

=A1.keys(EID,DEPT)

Set EID&DEPT fields as A1’s key

3

=A1(1).key()

[1,R&D]

4

=A1.keys()

Remove the key

5

=A1(1).key()

Return null because A1 doesn’t set a key

6

=A1.keys@t(EID,DEPT,HIREDATE)

Set EID and DEPT as A1’s basic keys and HIREDATE as time key

7

=A1.create()

Copy the key since table sequence T has one

8

=A7.insert(0,1,"Jack","HR",3000,date("2022-03-09"))

9

=A8(1).key()

[1,HR]; here values of basic keys are returned

Related functions:

r.key()

v.v()