I have a table in an Oracle database. An Index has mysteriously disappeared. Is there any way to find out how that happened? I am using Toad for Oracle Version 9.5.0.31
Thanks
I'm not sure you can find out after the fact but you can log future DROPs"
CREATE or replace TRIGGER your_name AFTER DROP
ON your_schema
pl/sql_block
You'll also have to create a logging table and insert into it.
Related
I installed PostgreSQL on new server.
When I try create new table or new data base, get this error:
column "rolcatupdate" does not exist.
How can I fix it?
What client/framework are you using for creating a table?
In Postgres 9.5 "rolcatupdate" is not anymore supported (list of pg_roles: https://www.postgresql.org/docs/current/static/view-pg-roles.html)
It might be that some client(s)/framework(s) still use it.
From the ChangeLog:
Remove the pg_authid catalog's rolcatupdate field, as it had no usefulness (Adam Brightwell)
I am using Eclipse, Java and a Derby database. I want to experiment with changing values that rewrite one of the tables in the db. Before starting the change I would like to copy the particular table (not in code) so that I can restore the original data if necessary. Sof ar googling and searching this site hasnt produced an answer. In Eclipse there is an option to export the db but it calls it a connection so I am not usre what would happen.
If you're not sure about how to connect to the database and issue sql statements, you will need to learn about JDBC. This is a good place to start.
If you're asking about the SQL, it's pretty straight forward. You can create a table based on a select statement.
e.g.
create table table2 as select * from table1 with no data;
Derby is a little strange in this area. You must specify the with no data, and the created table will be empty. You can then issue an insert that will populate the new table if you wish.
insert into table2 select * from table1;
The new table will not have indexes. You will need to create them if you want them. It might retain the primary key. You should check that if you're testing against it. If it doesn't retain the primary key, you should create the primary key before inserting data into the table.
In Eclipse there is an option to export the db but it calls it a connection so I am not sure what would happen.
If what Eclipse does isn't clear for you, you can just as well zip your entire database directory (content of DERBY_HOME env. variable) into an archive. The database must not be running while you make the backup.
I am getting this error when I ran:
alter table tablename add column columnname varchar(1) default 'N';
DB2 SQL Error: SQLCODE=-911, SQLSTATE=40001, SQLERRMC=68
How to solve it?
The alter statement wants to get an X lock on this row in SYSIBM.SYSTABLES. There is an open transaction that has this row/index value in an incompatible lock state. This lock that caused the timeout could even be from an open cursor that reads this row with an RS or RR isolation level.
Terminate any other SQL currently trying to query SYSTABLES and any utilities that may be trying to update SYSTABLES like reorg and runstats then try the alter again.
See DB2 Info center (I picked the one for DB2 10, most likely this error code is the same in other versions, but doublecheck!).
Seems there is a transaction open on your table, that prevents your alter command from execution.
after you have Altered a table you need to Reorg: reade up on it here:
Run the runstats script, which is a DB2 script, at regular intervals and set the script to gather RUNSTATS WITH DISTRIBUTION AND DETAILED INDEXES ALL.
In addition to running the runstats scripts regularly, you can perform the following tasks to avoid the problem:
Use REOPT ONCE or REOPT ALWAYS with the command-line interface (CLI ) packages to change the query optimization behavior.
In the DB2 database, change the table to make it volatile. Volatile tables indicate to the DB2 optimizer that the table cardinality can change significantly at run time (from empty to large and vice versa). Therefore, DB2 uses an index to access a table rather than a table scan.
I have a need to change the length of CHAR columns in tables in a PostgreSQL v7.4 database. This version did not support the ability to directly change the column type or size using the ALTER TABLE statement. So, directly altering a column from a CHAR(10) to CHAR(20) for instance isn't possible (yeah, I know, "use varchars", but that's not an option in my current circumstance). Anyone have any advice/tricks on how to best accomplish this? My initial thoughts:
-- Save the table's data in a new "save" table.
CREATE TABLE save_data AS SELECT * FROM table_to_change;
-- Drop the columns from the first column to be changed on down.
ALTER TABLE table_to_change DROP column_name1; -- for each column starting with the first one that needs to be modified
ALTER TABLE table_to_change DROP column_name2;
...
-- Add the columns back, using the new size for the CHAR column
ALTER TABLE table_to_change ADD column_name1 CHAR(new_size); -- for each column dropped above
ALTER TABLE table_to_change ADD column_name2...
-- Copy the data bace from the "save" table
UPDATE table_to_change
SET column_name1=save_data.column_name1, -- for each column dropped/readded above
column_name2=save_date.column_name2,
...
FROM save_data
WHERE table_to_change.primary_key=save_data.primay_key;
Yuck! Hopefully there's a better way? Any suggestions appreciated. Thanks!
Not PostgreSQL, but in Oracle I have changed a column's type by:
Add a new column with a temporary name (ie: TMP_COL) and the new data type (ie: CHAR(20))
run an update query: UPDATE TBL SET TMP_COL = OLD_COL;
Drop OLD_COL
Rename TMP_COL to OLD_COL
I would dump the table contents to a flat file with COPY, drop the table, recreate it with the correct column setup, and then reload (with COPY again).
http://www.postgresql.org/docs/7.4/static/sql-copy.html
Is it acceptable to have downtime while performing this operation? Obviously what I've just described requires making the table unusable for a period of time, how long depends on the data size and hardware you're working with.
Edit: But COPY is quite a bit faster than INSERTs and UPDATEs. According to the docs you can make it even faster by using BINARY mode. BINARY makes it less compatible with other PGSQL installs but you won't care about that because you only want to load the data to the same instance that you dumped it from.
The best approach to your problem is to upgrade pg to something less archaic :)
Seriously. 7.4 is going to be removed from "supported versions" pretty soon, so I wouldn't wait for it to happen with 7.4 in production.
We have a table someone created in DB2. I have no idea how they created it. But when I edit the table, It edits just fine. But after edit I can not query the table at all THE COLUMN CANNOT BE ADDED TO THE TABLE BECAUSE THE TABLE HAS AN EDIT PROCEDURE.
I looked ibm site and found this how to edit table using procedure
But I have no idea how to do this.
Is there anything that I can do to fix this with out following the procedure mentioned in second link?
I restarted server, but still no help. First I'm not able to figure out why I get the error in first place.
I'm using DB Visualizer and DB2 on linux.
This is sometimes default behavior of DB2. We need to run reorgchk command to fix these errors. More info below..
http://publib.boulder.ibm.com/infocenter/db2luw/v9/index.jsp?topic=/com.ibm.db2.udb.admin.doc/doc/r0000888.htm
http://publib.boulder.ibm.com/infocenter/db2luw/v9/index.jsp?topic=/com.ibm.db2.udb.admin.doc/doc/c0023297.htm