Oracle trigger where clause updating
Here are few interview questions with answers found on the internet.As I don't have time to format these questions to wiki I am just posting them hoping someone to format them. Explain the difference between a hot backup and a cold backup and the benefits associated with each.The difference between the two is that the truncate command is a DDL operation and just moves the high water mark and produces few rollback data.
"updating primary key related to other foreign key.. Would you like to answer one of these unanswered questions instead?In Oracle 8 they will be able to be of the %ROWTYPE designation, or RECORD. It must come first in a PL/SQL stand alone file if it is used. In what order should a open/fetch/loop set of commands in a PL/SQL block be implemented if you use the %NOTFOUND cursor variable in the exit when statement? Expected answer: OPEN then FETCH then LOOP followed by the exit when. Poor data dictionary or library cache hit ratios, getting error ORA-04031.If not specified in this order will result in the final return being done twice because of the way the %NOTFOUND is handled by PL/SQL. What are SQLCODE and SQLERRM and why are they important for PL/SQL developers? Another indication is steadily decreasing performance with all other tuning parameters the same. What is the general guideline for sizing db_block_size and db_multi_block_read for an application that does many full table scans? The two should have a product equal to 64 or a multiple of 64. What is the fastest query method for a table Fetch by rowid 7. What initialization parameter should be turned on to get full TKPROF output?For a view to be inherently updatable, the following conditions must be met: In addition, if an inherently updatable view contains pseudocolumns or expressions, then you cannot update base table rows with an UPDATE statement that refers to any of these pseudocolumns or expressions.If you want a join view to be updatable, then all of the following conditions must be true: Generally, you should not rely on being able to perform an insert to a view unless you have specifically written an INSTEAD OF trigger for it.
They can be used in exception handling to report, or, store in an error log table, the error that occurred in the code. Another possible method is to just use the SHOW ERROR command, but this only shows errors. Once the trace file is generated you run the tkprof tool against the trace file and then look at the output from the tkprof tool. The major sort are parameter is the SORT_AREA_SIZe parameter. You can increase copy latches via the initialization parameter LOG_SIMULTANEOUS_COPIES to twice the number of CPUs on your system. Where can you get a list of all initialization parameters for your instance? This is bad since it makes tracking which table the constraint belongs to or what the constraint does harder. What happens if a tablespace clause is left off of a primary key constraint clause This results in the index that is automatically generated being placed in then users default tablespace. This can be prevented or mitigated by breaking the transaction into a set of smaller transactions or increasing the size of the rollback segments and their extents. How can you tell if a database object is invalid By checking the status column of the DBA_, ALL_ or USER_OBJECTS views, depending upon whether you own or only have permission on the view or are using a DBA account. A user is getting an ORA-00942 error yet you know you have granted them permission on the table, what else should you check You need to check that the user has specified the full name of the object (select empid from scott.emp; instead of select empid from emp;) or has a synonym that balls to the object (create synonym emp for scott.emp;) 14.