Differences

This shows you the differences between two versions of the page.

--- validtimetemporal [2015/07/22 09:52] – z0hpvk
+++ validtimetemporal [2025/03/08 22:24] (current) – external edit 127.0.0.1
@@ Line 1: / Line 1: @@
 ===== Valid Time Temporal =====
+==== Create Tables ====
 Create a period using existing columns
 <code>CREATE TABLE student_modules (
@@ Line 18: / Line 19: @@
   PERIOD FOR student_module_period
   );</code>
-We can now create **AS OF PERIOD FOR** queries
-<code>SELECT * FROM student_modules AS OF
+==== Viewing Data ====
-                 PERIOD FOR student_module_period TO_DATE('12-FEB-2013','DD-MON-YYYY') sm;</code>
+We can now create **AS OF PERIOD FOR** queries.\\
+The below query finds all students on a currently active course.
+<code>SELECT * FROM student_modules AS OF PERIOD FOR student_module_period SYSDATE sm;</code>
+Can also create **VERSIONS PERIOD FOR ... BETWEEN** queries.\\
+The below query finds all students that were active in the last week.
+<code>SELECT * FROM student_modules VERSIONS PERIOD FOR
+              student_module_period BETWEEN TRUNC(SYSDATE)-7 AND TRUNC(SYSDATE);</code>
+==== Using Flashback ====
+You can also use the DBMS_FLASHBACK_ARCHIVE.ENABLE_AT_VALID_TIME procedure
+<code>BEGIN
+  DBMS_FLASHBACK_ARCHIVE.ENABLE_AT_VALID_TIME ('ASOF','20-JUL-15 12.00.01 PM');
+END;
+BEGIN
+  DBMS_FLASHBACK_ARCHIVE.ENABLE_AT_VALID_TIME ('CURRENT');
+END;
+BEGIN
+  DBMS_FLASHBACK_ARCHIVE.ENABLE_AT_VALID_TIME ('ALL');
+END;</code>