Description:
Define the key(s) for an in-memory table.
Syntax:
T.keys(Ki,…)
Note:
The function defines key(s) Ki,…, which may include the time key, for in-memory table T.
Parameter:
Ki |
Key name; can be one or multiple keys; delete all keys of an in-memory table when the parameter is absent |
T |
An in-memory table |
Optios:
@t(…,KT) |
Set the last parameter KT as the time key and all other key fields constitute the basic key |
Return value:
An in-memory table
Example:
|
A |
|
1 |
=demo.cursor("select EID,NAME,GENDER from EMPLOYEE where EID<10") |
Return cursor of the retrieved data. |
2 |
=A1.memory() |
Return an in-memory table:
|
3 |
=A2.keys(EID,NAME) |
Set EID and NAME as the in-memory table’s keys. |
4 |
=A3(1).key() |
Get the keys of the first record and return the result:
|
5 |
=A2.keys() |
Delete all keys of the in-memory table. |
6 |
=A3(1).key() |
Query the keys of the first record and return null. |
7 |
=demo.cursor("select * from employee").memory() |
Return an in-memory table. |
8 |
=A7.keys@t(EID,HIREDATE) |
Set EID as the basic key and HIREDATE as the time key in A7’s in-memory table. |