Regular expression for validating date format ddmmyyyy
Variable declarations are one of the more obvious problems you'll meet with longer names. This is limited to 4,000 bytes (32,767 if you’re using extended data types).Let's look at a more subtle issue: The following query returns a comma-separated list of indexes for each table in your schema: This is all very well and good. So in 12.1 and 11.2, you needed 130 or more indexes on a table before you start running into issues.So it's only a matter of time before people create tables with longer names.
And you can be sure that someone, somewhere will start creating "self-documenting" indexes like: Create too many of these and your listagg query will throw frustrating ORA-01489 errors. The number in brackets how many characters Oracle trimmed from the results.But when it comes to naming things, we've made it harder than it ought to be. As a result, many people have asked for us to allow longer names. So even though the string above is only 67 characters, it needs 130 bytes!I know some of you are desperate to start Creating Tables With Ridiculously Long Names. If your dev team uses sloppy coding practices, there may be some traps waiting for you... But as we just saw, upgrade to 12.2 and the limit is now 128 bytes!There's a good chance you've already written code to handle the ORA-1489 errors. To do this, create the MV with the clause: This can lead to some scary looking execution plans! After all, your boss will round your figure to one or two significant digits anyway.So to keep the behaviour of your code the same, the default remains error. The point to remember is Oracle is reading the materialized view log. So the longer you leave it between refreshes, the more data there will be. So in 18.104.22.168 we introduced approx_count_distinct. This returns an estimate of how many different values there are in the target column.