So I had the pleasure of taking my first Oracle certification exam today: “Oracle Database: SQL Certified Expert”. I passed pretty easily, but am not very happy with the exam and the experience. First, the test. I am sure I missed my share of question by not paying close enough attention to the details. However,… Read More »
Continuation of my notes to review before taking the 1Z0-047 certification. Hierarchical Queries fork is the term for a node that has 2 or more children If you have both JOIN and CONNECT BY, the join is processed before the connect by Order of START WITH and CONNECT BY clauses don’t matter with respect to… Read More »
Continuation of my notes to review before taking the 1Z0-047 certification. Rollup / Cube / Grouping Sets grouping(column_name) = 1 indicates a superaggregate row Data Dictionary Adding Comments: Comments can be added to tables, columns, indextype, etc.: comment on table ships is ‘Listing of all ships’; comment on column ships.capacity is ‘Maximum number of passengers’;… Read More »
Continuation of my notes to review before taking the 1Z0-047 certification. Sequences Rules: CURRVAL can’t be invoked in a session before NEXTVAL has been called in the same session If NEXTVAL used in statement, counter incremented even if statement doesn’t complete successfully CURRVAL / NEXTVAL can’t be used as column default CURRVAL / NEXTVAL can’t… Read More »
Continuation of my notes to review before taking the 1Z0-047 certification. Aggregate Functions Can only be nested 2 levels deep: select avg(sum(count(x))) from table will throw an exception The GROUP BY and HAVING clauses can appear in either order: select mod(rownum,10), count(*) from dual connect by level
Nothing groundbreaking here… Just some notes of some things I don’t want to forget when taking the exam. There will most likely be a few more posts like this one in the near future as I continue to study. Object Naming – After first character, can contain letters, numbers, $, _, and # without being… Read More »