query transaction filter (BEFORE/AFTER)

Summary

Fix/Enhancement of #132 (closed)

The issue was misclassified as bug, the documentation was no very helpful, apparently. Since the implementation was very straight forward, I decided to do it anyways.

Focus

The mysql backend api has not changed. Only the CQL parser (CQLParser.g4/CQLLexer.g4) and the filter implementation of the server (TransactionFilter.java) had to be extended.

Test Environment

Tests in caosdb-pyinttest!6 (merged) should be sufficient

Check List for the Author

• All automated tests pass
• Reference related Issues
• Up-to-date CHANGELOG.md
• Annotations in code (Gitlab comments)
  • Intent of new code
  • Problems with old code
  • Why this implementation?

Check List for the Reviewer

• I understand the intent of this MR
• All automated tests pass
• Up-to-date CHANGELOG.md
• The test environment setup works and the intended behavior is reproducible in the test environment
• In-code documentation and comments are up-to-date.
• Check: Are there spezifications? Are they satisfied?

For further good practices have a look at our review guidelines.

doc/Query.md

@@ -226,14 +226,13 @@ The following query returns entities which have a _pname1_ property with any val
 ### TransactionFilter
 
 *Definition*
- sugar:: `HAS BEEN` | `HAVE BEEN` | `HAD BEEN` | `WAS` | `IS` | 
+ sugar:: `HAS BEEN` | `HAVE BEEN` | `HAD BEEN` | `WAS` | `IS`
  negated_sugar:: `HAS NOT BEEN` | `HASN'T BEEN` | `WAS NOT` | `WASN'T` | `IS NOT` | `ISN'T`  | `HAVN'T BEEN` | `HAVE NOT BEEN` | `HADN'T BEEN` | `HAD NOT BEEN`
  by_clause:: `BY (ME | username | SOMEONE ELSE (BUT ME)? | SOMEONE ELSE BUT username)`
- date:: A date string of the form `YYYY-MM-DD`
- datetime:: A datetime string of the form `YYYY-MM-DD hh:mm:ss`
- time_clause:: `ON ($date|$datetime) ` Here is plenty of room for more syntactic sugar, e.g. a `TODAY` keyword, and more funcionality, e.g. ranges.  
+ datetime:: A datetime string of the form `YYYY[-MM[-DD(T| )[hh[:mm[:ss[.nnn][(+|-)zzzz]]]]]]`
+ time_clause:: `[AT|ON|IN|BEFORE|AFTER|UNTIL|SINCE] (datetime) `
 
-`FIND ename WHICH ($sugar|$negated_sugar)? (NOT)? (CREATED|INSERTED|UPDATED|DELETED) (by_clause time_clause?| time_clause by_clause?)`
+`FIND ename WHICH (sugar|negated_sugar)? (NOT)? (CREATED|INSERTED|UPDATED) (by_clause time_clause?| time_clause by_clause?)`
 
 *Examples*
 
@@ -247,8 +246,9 @@ The following query returns entities which have a _pname1_ property with any val
 
 `FIND ename WHICH HAS BEEN CREATED BY erwin`
 
-`FIND ename . CREATED BY erwin ON `
+`FIND ename WHICH HAS BEEN INSERTED SINCE 2021-04`
 
+Note that `SINCE` and `UNTIL` are inclusive, while `BEFORE` and `AFTER` are not.
 
 
 ### File Location