In Alan, how do I annotate a date field so that it is autofilled with the current date upon entry creation.
for example:
'Creation Date': natural 'date'
In your application.alan annotate the number property as follows:
'Date': integer 'date' #default: today
FYI, for date-and-time properties you can use the now default.
More info: https://alan-platform.com/pages/docs/model/30/application/grammar.html
Related
I have my data loaded on Neo4j instance where, for each node, I recorded the temporal information in a property key (.time) following the format:
YYYY-MM-DD
example: time: 1937-01-01
These are all strings, that I would like to convert into datetime as to use them in Neo4j Bloom and various time-based queries. I tried to use the following formula (as well as various variations of it):
MATCH (p:Image)
WHERE p.time IS NOT NULL
SET p.time = datetime({ epochMillis: apoc.date.parse(p.time, 's', 'yyyy-MM-dd HH:mm:ss') })
without success. I always get the error
Failed to invoke function `apoc.date.parse`: Caused by: java.text.ParseException: Unparseable date: "1891-01-01"
Any idea what I am doing wrong and how to transform date as string to datetime ?
I read some previous posts on the subject but I couldn't find a satisfying answer...
Your data format and the format you specified in the apoc function don't match. Also, you might wanna parse milliseconds, rather than seconds, since you are using epochMillis field.
Try this:
MATCH (p:Image)
WHERE p.time IS NOT NULL AND p.time <> ""
SET p.time = datetime({ epochMillis: apoc.date.parse(p.time + " 00:00:00", 'ms', 'yyyy-MM-dd HH:mm:ss') })
Ok, then for your error you will have to use your previous format, and convert your date into your format. The error basically meant that millisecond component is not present.
You can use function date() if you have only date part without time. You can call date('2015-07-21') directly.
https://neo4j.com/docs/cypher-manual/current/functions/temporal/#functions-date-create-string
I am new to DynamoDB. I wish to create a table which using DeviceID as the hash key, Timestamp as my range key and some data.
{ DeviceID: 123, Timestamp: "2016-11-11T17:21:07.5272333Z", X: 12, Y: 35 }
In SQL, we can use datetime type for Timestamp, but in DynamoDB there is none.
What data type should I use? String? Number?
For the chosen data type, what kind of timestamp format should I write in? ISO format (e.g: 2016-11-11T17:21:07.5272333Z) or epoch time (e.g: 1478943038816)?
I need to search through the table through a range of time, e.g: 1/1/2015 10:00:00am until 31/12/2016 11:00:00pm
The String data type should be used for Date or Timestamp.
You can use the String data type to represent a date or a timestamp.
One way to do this is by using ISO 8601 strings, as shown in these
examples:
2016-02-15
2015-12-21T17:42:34Z
20150311T122706Z
DynamoDB Data type for Date or Timestamp
Yes, the Range queries are supported when the date is stored as String. The BETWEEN can be used on FilterExpresssion. I have got the items in the result using the below filter expressions.
FilterExpression without time:-
FilterExpression : 'createdate between :val1 and :val2',
ExpressionAttributeValues : {
':hkey' : year_val,
':rkey' : title,
":val1" : "2010-01-01",
":val2" : "2010-12-31"
}
FilterExpression with time:-
FilterExpression : 'createdate between :val1 and :val2',
ExpressionAttributeValues : {
':hkey' : year_val,
':rkey' : title,
":val1" : "2010-01-01T00:00:00",
":val2" : "2010-12-31T00:00:00"
}
Database Values:-
Format 1 - with timezone:
{"Item":{"createdate":{"S":"2010-12-21T17:42:34+00:00"},"title":{"S":"The Big New Movie 2010"},"yearkey":{"N":"2010"},"info":{"M":{"rating":{"N":"0"},"plot":{"S":"Nothing happens at all."}}}}}
Format 2 - without timezone:-
{"Item":{"createdate":{"S":"2010-12-21T17:42:34Z"},"title":{"S":"The Big New Movie 2010"},"yearkey":{"N":"2010"},"info":{"M":{"rating":{"N":"0"},"plot":{"S":"Nothing happens at all."}}}}}
Data type depends on your requirements.
You may use String using ISO format or Number using epoch format.
The advantage of ISO format (String) is human readability however DynamoDB does not support Time To Live (TTL) for this format. All filters work such as 'between' and 'range' as explained by notionquest.
Time To Live (TTL) for DynamoDB allows you to define when items in a table expire so that they can be automatically deleted from the database.
The advantage of using epoch format (Number) is that you can use the TTL feature and all filters.
TLDR;
Epoch format (Number type) - Can use Time To Live
ISO format (String type) - Cannot use Time To Live but is more human readable
for me to be able to filter out results when sending a query request, I used epoch format for DateTime, it is more efficient than using string.
imagine these scenarios: last 31 days, last 24 hours, ... again all is possible using the string format since it also has begins_with operator(please check 3rd example in below link on AWS doc) but numeric values are much more efficient in terms of performance while sorting(comparing) & calculation.
https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Query.html#Query.KeyConditionExpressions
it is easy to convert date-time to epoch format
Javascript:
var date = new Date();
var epoch = date.getTime();
// converting back to date-time
var initial_date = new Date(epoch);
C#
var date = DateTime.UtcNow;
var epoch = new DateTimeOffset(date).ToUnixTimeSeconds();
// converting back to date-time
var initial_date = DateTimeOffset.FromUnixTimeSeconds(epoch);
Python
import time
epoch = time.time()
# converting back to date-time
initial_date = time.gmtime(epoch )
The Number data type OR the String data type
can be used for Date or Timestamp - not just String as the Accepted Answer on this Question incorrectly singles out while ignoring Number.
You can use the number data type to represent a date or a timestamp. One way to do this is by using epoch time—the number of seconds since 00:00:00 UTC on 1 January 1970. For example, the epoch time 1437136300 represents 12:31:40 PM UTC on 17 July 2015.
For more information, see http://en.wikipedia.org/wiki/Unix_time.
...
You can use the String data type to represent a date or a timestamp. One way to do this is by using ISO 8601 strings, as shown in these examples:
2016-02-15
2015-12-21T17:42:34Z
20150311T122706Z
For more information, see http://en.wikipedia.org/wiki/ISO_8601.
DynamoDB Data type for Date or Timestamp
I have to stamp with info a createdDateTime field's Table,
I used this simple code:
info( strfmt("Date-Time: %1" , myTableDate.createdDateTime) );
On myTableDate I have this value: 05/08/2015 12:48:57
On video in info I see this message:
Date-time: 05/08/2015 10:48:57
I see two hours less than the value stored in table. The field createdDateTime is the standard table's field .
Thanks all,
enjoy!
You will have to correct for timezone, as strFmt will not do it for you:
info( strfmt("Date-Time: %1", DateTimeUtil::applyTimeZoneOffset(myTableDate.createdDateTime, DateTimeUtil::getUserPreferredTimeZone()));
You need correct a timeZone^ DateTimeUtil::getUserPreferredTimeZone()
I have an Oracle table which has a date column ( say its name is start_date) that has stored date as UTC date. I have another column that stores a timezone (like 'America/Los_Angeles'). My requirement is I need to display the date column with timestamp corresponding to the timezone stored in the timezone column.
I initially wrote a function that accepts utc_date and the timezone and returns the date as below:
return utc_date + (SUBSTR (TZ_OFFSET (timezone), 1, 1) || '1')
* TO_DSINTERVAL (
'0 '
|| SUBSTR (TZ_OFFSET (timezone), 2, 5)
|| ':00');
but I realized a flaw. It calculates offset based on current time. So it now returns -00 08:00:00.000000 for Los_Angeles. But if the date stored in the utc_date was a date when daylight was enforced, the tz_offset value is not valid anymore. Can someone provide me some pointers how can I approach this problem?
I found a solution to my problem. Instead of relying on TZ_OFFSET, I decided to do the following
return cast(from_tz(cast(utc_date as timestamp),'UTC') at time zone timezone as date);
This is returning me the desired date. If anyone see a flaw let me know
I have a DateTime type column named "CreatedDate" in my sql table, and am passing the value for this column by using "DateTime.Now" from my asp.net application....
The datas in my CreatedDate column are,
CreatedDate
-----------
2012-05-07 18:56:17.487
2012-05-07 18:56:28.443
2012-05-07 19:21:24.497
2012-05-14 15:22:04.587
I need to get the datas with this CreatedDate.
in my entity framework I tried the condition like
DataAccess.Entities dataEntities = new DataAccess.Entities();
DataAccess.Employee employee = dataEntities.Employees
.First(e => e.CreatedDate == DateTime.Today);
like this, I have data for this date(2012-05-14) , but the mininutes part differes (the DateTime.Today gives '2012-05-14 12:00:000' like this) here, and it shows error like, sequence contains no element....
How can I compare the 'Date' alone in Linq.....can anyone help me here,,,
Use the Date Property on the DateTime object
CreatedDate.Date==DateTime.Today
So your code will be
DataAccess.Employee employee=dataEntities.
Employees.First(e=>e.CreatedDate.Date==DateTime.Today);
Date Property returns the Date Component of the DateTime object and the time value set to 12:00:00 midnight (00:00:00).
Try this:
DataAccess.Employee employee =
dataEntities.Employees.First(e=>e.CreatedDate.Date==DateTime.Today)
I just declared two variable like
DateTime date1=DateTime.Now.Date;
DateTime date2=DateTime.Now.Date.AddDays(1);
and in the condition I used these variables like
DataAccess.Employee employee = dataEntities.Employees
.First(e => e.CreatedDate >= date1
&& e.CreatedDate < date2);
its working....