Date and time types¶
This topic will describe the DATE, TIME, DATETIME, and TIMESTAMP types.
While inserting time-type property values, except for TIMESTAMP, NebulaGraph transforms them to a UTC time according to the time zone specified with the timezone_name parameter in the configuration files.
Note
To change the time zone, modify the timezone_name value in the configuration files of all NebulaGraph services.
date(),time(),datetime(), andtimestamp()all accept empty parameters to return the current date, time, and datetime.
date(),time(), anddatetime()all accept the property name to return a specific property value of itself. For example,date().monthreturns the current month, whiletime("02:59:40").minutereturns the minutes of the importing time.
OpenCypher Compatibility¶
In nGQL:
- Year, month, day, hour, minute, and second are supported, while the millisecond is not supported.
localdatetime()andduration()are not supported.
- Most string time formats are not supported. The exceptions are
YYYY-MM-DDThh:mm:ssandYYYY-MM-DD hh:mm:ss.
DATE¶
The DATE type is used for values with a date part but no time part. Nebula Graph retrieves and displays DATE values in the YYYY-MM-DD format. The supported range is -32768-01-01 to 32767-12-31.
The properties of date() include year, month, and day.
TIME¶
The TIME type is used for values with a time part but no date part. Nebula Graph retrieves and displays TIME values in hh:mm:ss.msmsmsususus format. The supported range is 00:00:00.000000 to 23:59:59.999999.
The properties of time() include hour, minute, and second.
DATETIME¶
The DATETIME type is used for values that contain both date and time parts. Nebula Graph retrieves and displays DATETIME values in YYYY-MM-DDThh:mm:ss.msmsmsususus format. The supported range is -32768-01-01T00:00:00.000000 to 32767-12-31T23:59:59.999999.
The properties of datetime() include year, month, day, hour, minute, and second.
TIMESTAMP¶
The TIMESTAMP data type is used for values that contain both date and time parts. It has a range of 1970-01-01T00:00:01 UTC to 2262-04-11T23:47:16 UTC.
TIMESTAMP has the following features:
- Stored and displayed in the form of a timestamp, such as
1615974839, which means2021-03-17T17:53:59.
- Supported
TIMESTAMPquerying methods: timestamp andtimestamp()function.
- Supported
TIMESTAMPinserting methods: timestamp,timestamp()function, andnow()function.
-
timestamp()function accepts empty parameters to get the timestamp of the current time zone and also accepts a string type parameter.# Return the current time. nebula> RETURN timestamp(); +-------------+ | timestamp() | +-------------+ | 1625469277 | +-------------+ # Return the specified time. nebula> RETURN timestamp("2021-07-05T06:18:43.984000"); +-----------------------------------------+ | timestamp("2021-07-05T06:18:43.984000") | +-----------------------------------------+ | 1625465923 | +-----------------------------------------+
- The underlying storage data type is int64.
Examples¶
-
Create a tag named
date1with three properties:DATE,TIME, andDATETIME.nebula> CREATE TAG IF NOT EXISTS date1(p1 date, p2 time, p3 datetime); -
Insert a vertex named
test1.nebula> INSERT VERTEX date1(p1, p2, p3) VALUES "test1":(date("2021-03-17"), time("17:53:59"), datetime("2021-03-17T17:53:59")); -
Return the content of the property
p1ontest1.nebula> CREATE TAG INDEX IF NOT EXISTS date1_index ON date1(p1); nebula> REBUILD TAG INDEX date1_index; nebula> MATCH (v:date1) RETURN v.p1; +------------+ | v.p1 | +------------+ | 2021-03-17 | +------------+ -
Create a tag named
schoolwith the property ofTIMESTAMP.nebula> CREATE TAG IF NOT EXISTS school(name string , found_time timestamp); -
Insert a vertex named
DUTwith a found-time timestamp of"1988-03-01T08:00:00".# Insert as a timestamp. The corresponding timestamp of 1988-03-01T08:00:00 is 573177600, or 573206400 UTC. nebula> INSERT VERTEX school(name, found_time) VALUES "DUT":("DUT", 573206400); # Insert in the form of date and time. nebula> INSERT VERTEX school(name, found_time) VALUES "DUT":("DUT", timestamp("1988-03-01T08:00:00")); -
Insert a vertex named
dutand store time withnow()ortimestamp()functions.# Use now() function to store time nebula> INSERT VERTEX school(name, found_time) VALUES "dut":("dut", now()); # Use timestamp() function to store time nebula> INSERT VERTEX school(name, found_time) VALUES "dut":("dut", timestamp());
You can also use WITH statement to set a specific date and time. For example:
nebula> WITH time({hour: 12, minute: 31, second: 14, millisecond:111, microsecond: 222}) AS d RETURN d;
+-----------------+
| d |
+-----------------+
| 12:31:14.111222 |
+-----------------+
nebula> WITH date({year: 1984, month: 10, day: 11}) AS x RETURN x + 1;
+------------+
| (x+1) |
+------------+
| 1984-10-12 |
+------------+