Does Oracle NoSQL provide a function allowing to generate the system timestamp for a column - oracle-nosql

Question

does Oracle NoSQL provide SDK API or sql build-in function which can automatically generate the system timestamp for a column?
We have a column called timeUpdated which keep the time when any data updated in the same row, we can pass the system time when updating that row, but it could be a little gap with the time when the data is committed at database finally. The timestamp passed by will be the local time of our application servers

Answer 1

you can use current_time() - Returns the current time in UTC, as a timestamp value with millisecond precision.
sql-> create table TEST ( a integer, b timestamp(3), primary key (a));
Statement completed successfully
sql-> insert into TEST values (1, current_time());
{"NumRowsInserted":1}
1 row returned
sql-> select * from TEST;
{"a":1,"b":"2021-06-15T09:52:01.561Z"}
sql-> update TEST set b = current_time() where a =1;
{"NumRowsUpdated":1}
1 row returned
sql-> select * from ping;
{"a":1,"b":"2021-06-15T09:53:24.101Z"}
But you can also use the modification_time function allows you to see the most recent modification time (in UTC) of a row.
sql-> select id, firstname, lastname, modification_time($u) FROM users $u ;
{"id":4,"firstname":"Peter","lastname":"Smith","Column_4":"2021-06-08T08:27:19.640Z"}
{"id":2,"firstname":"John","lastname":"Anderson","Column_4":"2021-06-08T08:27:19.624Z"}
{"id":5,"firstname":"Dana","lastname":"Scully","Column_4":"2021-06-08T08:27:19.644Z"}
{"id":1,"firstname":"David","lastname":"Morrison","Column_4":"2021-06-08T08:27:19.613Z"}
{"id":3,"firstname":"John","lastname":"Morgan","Column_4":"2021-06-08T08:27:19.630Z"}
Here the table, this table does not have a timestamp column
sql-> desc as json table users;
{
"json_version" : 1,
"type" : "table",
"name" : "Users",
"fields" : [{
"name" : "id",
"type" : "INTEGER",
"nullable" : false
}, {
"name" : "firstname",
"type" : "STRING",
"nullable" : true
}, {
"name" : "lastname",
"type" : "STRING",
"nullable" : true
}, {
"name" : "income",
"type" : "INTEGER",
"nullable" : true
}],
"primaryKey" : ["id"],
"shardKey" : ["id"]
}
In this case, this is the NoSQL system that is managing the date but it seems that in your use-case, you want to manage your own column