Quote by @DAC In short: SID = the unique name of your DB, ServiceName = the alias used when connecting Not strictly true. SID = unique name of the INSTANCE (eg the oracle process running on the machine). Oracle considers the “Database” to be the files. Service Name = alias to an INSTANCE (or many … Read more
I fixed this issue by correcting my jdbc string. For example, the correct jdbc string should be… jdbc:oracle:thin:@myserver:1521/XE But the jdbs string I was using is … jdbc:oracle:thin:@myserver:1521:XE (Note: between 1521 and XE should be a /) This bad jdbc string give me a ORA-12505 error too.
There are a few ways depending on what version you have – see the oracle documentation on string aggregation techniques. A very common one is to use LISTAGG: SELECT pid, LISTAGG(Desc, ‘ ‘) WITHIN GROUP (ORDER BY seq) AS description FROM B GROUP BY pid; Then join to A to pick out the pids you … Read more
SELECT train, dest, time FROM ( SELECT train, dest, time, RANK() OVER (PARTITION BY train ORDER BY time DESC) dest_rank FROM traintable ) where dest_rank = 1
You can query the USER_TAB_COLUMNS table for table column metadata. SELECT table_name, column_name, data_type, data_length FROM USER_TAB_COLUMNS WHERE table_name=”MYTABLE”
RANK() gives you the ranking within your ordered partition. Ties are assigned the same rank, with the next ranking(s) skipped. So, if you have 3 items at rank 2, the next rank listed would be ranked 5. DENSE_RANK() again gives you the ranking within your ordered partition, but the ranks are consecutive. No ranks are … Read more
Oracle’s very own Tom Kyte has a fantastic repository on every type of performance problem imaginable on http://asktom.oracle.com. He usually takes the time to recreate specific problems and gives very detailed explanations.
I know this is an old thread, but I just stumbled upon it and I feel this has not been explained completely. There is a huge difference in SQL*Plus between the meaning of a / and a ; because they work differently. The ; ends a SQL statement, whereas the / executes whatever is in … Read more
In Oracle 12.2 and above the maximum object name length is 128 bytes. In Oracle 12.1 and below the maximum object name length is 30 bytes.
No. There is no such option available from Oracle SQL Developer. You have to execute a query by hand or use other tool (For instance PLSQL Developer has such option). The following SQL is that one used by PLSQL Developer: select table_name, constraint_name, status, owner from all_constraints where r_owner = :r_owner and constraint_type=”R” and r_constraint_name … Read more