During the months I have been writing my book, I have not had much time to participate in the Usenet newsgroup comp.databases.oracle.server, however I have been glancing through the headings from time to time, and jotting down a note of some of the more commonly occuring questions.
This list is just the start of a few of those questions, and over the next few months I shall try to write up a couple of answers each week.
| Title | Content | Last update |
|---|---|---|
| glogin | Setting up an 'environment' for SQL*Plus (correction) | 29-Nov-2000 |
| Row size | How big is a row ? (addendum: what about rows that grow over time). | 27-Nov-2000 |
| dbms_output | Why can't I see the output from dbms_output ? | 24-Nov-2000 |
| Free Space | How do I find out how much space is actually USED by a table/index | 13-Nov-2000 |
| Redo Copy | The number of redo copy latch misses reported in V$LATCH is a large fraction of the gets. What should I do ? | 29-Aug-2000 |
| ALERT problem | I keep getting errors in the alert log 'Thread XXX cannot allocate new log - checkpoint not complete'. Is this serious ? | 29-Aug-2000 |
| Resizing Logs | How do I increase the size of my log files ? | 29-Aug-2000 |
| Sleep | Is there a way to suspend a task for a period of time ? | 14-Aug-2000 |
| Sequence Losses | Why do I keep losing sequence numbers ? | 09-Aug-2000 |
| Rename Column | How do you rename a column in a table ? | 31-Jul-2000 |
| Starting SQL*Plus | Why does everyone except SYSTEM (and possibly SYS) get a strange error message when starting up SQL*Plus ? | 31-Jul-2000 |
| Number sizing | How much space does a number take up ? | 31-Jul-2000 |
| Autonumber | How do you create an 'auto number' or 'auto increment' column similar to the offering from Microsoft's SQL Server ? | 24-Jul-2000 |
| Bits | What bitwise operations does Oracle support ? | |
| Command line | How can I start an SQL*Plus batch without showing the id/password on the command line ? | |
| Indexes | Which of my indexes are redundant and can be dropped ? | |
| utl_file lines | The line length in utl_file is limited to 1023 bytes - is there a workaround ? | |
| Rollback | After I do a COMMIT, there is still a lot of space used in the rollback tablespace, why is this ? | |
| ORA-01555 | I often get "ORA-01555 Snapshot too old" when running reports. What is this and how do I stop it happening ? | |
| Char/Varchar2 | Why should I use VARCHAR2() instead of CHAR() types ? | |
| Temp space | My temporary tablespace never clears down, what should I do ? | |
| Scheduling | How can I make a particular piece of code run at a regularly scheduled time ? | |
| dbms_output | I lose the leading spaces and blank lines when I try to format output through the dbms_output package. How can I tidy this up ? | |
| Block sizes | How do I change the database block size ? | |
| Move db | How can I move the database to a different machine ? | |
| Space Contradication | Why do different data dictionary views give me different figures for the amount of space used by a table/index ? | |
| AUTOTRACE | I get strange error messages when trying to use AUTOTRACE in SQL*Plus. How do I fix this ? | |
| Explain Plan | Oracle seems to be very slow reporting large execution plans through explain plan. Is there any way to speed this up. | |
| More files | How do I increase the number of files in the database. I am getting error ORA-01520 / ORA-00059 when trying to add a new tablespace / data file , what should I do ?. | |
| Connect problem | (UNIX) I can't run SQL*Plus and all the other tools on the server unless I connect as the 'oracle' unix account - why not ? | |
| Writing files | Why am I getting errors when I try to use utl_file to write a flat file ? | |
| DDL in PL/SQL | How can I create/drop/truncate a table inside a PL/SQL block ? | |
| Flat export | How do I export a database table to a flat file ? | |
| Connect time | A connection to the database (ca. v7.3) is starting to take a long time, why ? | |
| Duplicates | How do I remove duplicate rows from a table ? | |
| Record Sets | How do I return a set of records from a pl/sql procedure ? | |
| Two table update | How do I update one table with values from another table ? | |
| Ampersand & | How do I get SQL*Plus to store an '&' in the database ? | |
| SQL*Plus prompt | How can I set the SQL*Plus prompt to something useful ? | |
| Top 10 | How do I report the top 10 product members of the sales team in each state/county ? | |
| Count(*) | Is there a good way of counting the number of rows in a table ? | |
| Move table | How do I move a table from one tablespace to another ? | |
| Defragment tablespace | How can I reclaim unusable fragments of space in a tablespace ? | |
| Drop column | How do I drop a column from a table ? | |
| Hex to Dec | How can I convert numbers from Hex to Decimal (or any other bases) ? | |
| Random numbers | Is it possible to generate a set of random numbers ? | |
| Random rows | How can I select a random collection of rows from a table ? | |
| Locked Row | How do you find out who is locking a row that you need ? | |
| Locked Rows | How do you identify all the locked rows in a table ? | |
| Case Insensitive | How do you write a query that ignores the effects of upper and lower case ? | |
| Privileges in procedures | I have a PL/SQL procedure which won't work because of 'insufficient privileges', but when I work through the steps in SQL*Plus it all seems to work. What privileges am I missing ? | |
| One extent | How much benefit is there in rebuilding a table/index so that it fits in a single extent ? | |
| Autorun at login | Can I make a procedure run every time someone logs on to the system ? | |
| Indexes and PK/UK | How can I identify which index represents which primary or unique key constraint ? | |
| Rows affected | Can I find out how many rows will be affected by an SQL statement without actually running it ? | |
| Rows affected | How can I find out how many rows were affected by an SQL statement after I have executed it ? | |
| Slow PL/SQL | I have some SQL that runs very quickly under raw SQL*Plus, but takes forever to complete under PL/SQL - why does this happen ? | |
| Emptying a table | What's the quickest way of deleting all the data in a table ? |