I am new to Oracle DB and I am using Oracle SQL Developer (Ver 3.0.02) to query the DB.
I wanted to explicitly set one column to null?
How do I do that in the SQL Developer GUI?
Previously in MSSQL, clicking CTRL+0 will explicitly set the value to null.
How about Oracle SQL Developer?
Thanks
You'll have to write the SQL DML yourself explicitly.
i.e.
UPDATE <table>
SET <column> = NULL;
Once it has completed you'll need to commit your updates
commit;
If you only want to set certain records to NULL use a WHERE clause in your UPDATE statement.
As your original question is pretty vague I hope this covers what you want.
If you want to use the GUI... click/double-click the table and select the Data tab. Click in the column value you want to set to (null). Select the value and delete it. Hit the commit button (green check-mark button). It should now be null.
More info here:
How to use the SQL Worksheet in SQL Developer to Insert, Update and Delete Data
Use Shift+Del.
More info:
Shift+Del combination key set a field to null when you filled a field by a value and you changed your decision and you want to make it null. It is useful and I amazed from the other answers that give strange solutions.
It is clear that most people who haven't used SQL Server Enterprise Manager don't understand the question (i.e. Justin Cave).
I came upon this post when I wanted to know the same thing.
Using SQL Server, when you are editing your data through the MS SQL Server GUI Tools, you can use a KEYBOARD SHORTCUT to insert a NULL rather than having just an EMPTY CELL, as they aren't the same thing. An empty cell can have a space in it, rather than being NULL, even if it is technically empty. The difference is when you intentionally WANT to put a NULL in a cell rather than a SPACE or to empty it and NOT using a SQL statement to do so.
So, the question really is, how do I put a NULL value in the cell INSTEAD of a space to empty the cell?
I think the answer is, that the way the Oracle Developer GUI works, is as Laniel indicated above, And THAT should be marked as the answer to this question.
Oracle Developer seems to default to NULL when you empty a cell the way the op is describing it.
Additionally, you can force Oracle Developer to change how your null cells look by changing the color of the background color to further demonstrate when a cell holds a null:
Tools->Preferences->Advanced->Display Null Using Background Color
or even the VALUE it shows when it's null:
Tools->Preferences->Advanced->Display Null Value As
Hope that helps in your transition.
Related
I am using sequences to create IDs, so while executing insert stored procedure it will create unique value for ID. But after some time it is losing the definition for the sequence.
Not sure why this is happening again and again and how to solve the problem?
I am using Oracle SQL Developer and in the edit table property there is 'Identity Column' setting. See below:
Next step is setting up trigger and sequence:
It was working fine for some time until this property defaulted. Now it is not there anymore:
Still have this trigger and sequence object in the schema and able to setup again but it will break later.
How to avoid this problem in future?
I think it is just a bug/limitation in your client software, Oracle SQL Developer. The "Identity Column" tab is a handy way to create the corresponding sequence and trigger but it doesn't seem to recognise existing elements. I've just verified my own system and that's exactly what happens.
It makes sense, because adding a new sequence and trigger is a pretty straightforward task (all you need is a template) but displaying current sequence is hard given that a trigger can implement any conceivable logic. Surely it could be done but the cost-benefit ratio probably left things this way.
In short, your app is not broken so nothing needs to be fixed on your side.
This is what I received from IT support regarding the issue:
A few possibilities that might cause this:
1 - Another user with limited privileges might be editing the table using SQL Developer. In this case, if this user's privilege is not enough to obtain the sequence and/or trigger information from the database, the tool might leave the fields blank and disable it when table changes are saved.
2 - The objects are being changed or removed outside of SQL Developer, causing it to lose the information. In my tests I noticed that dropping the trigger and recreating it with the same name caused the identity property information to be lost on SQL Developer.
Even being the trigger enabled, and working for inserts it could not retrieve the information.
Then, if I run an alter trigger to enable it (even tough dba_trigger is reporting it as already enabled), SQL Developer will list the information again:
ALTER TRIGGER "AWS"."TABLE1_TRG" ENABLE;
So it looks like there are some issues with the SQL Developer, that is causing this behavior.
Next time it happen, please check if the trigger still exist on the database and is enabled with the query below:
select owner, trigger_name, TRIGGER_TYPE, TRIGGERING_EVENT, TABLE_OWNER, TABLE_NAME, STATUS
from dba_triggers
where trigger_name = 'ENTER_YOUR_TRG_NAME'; --Just change the trigger name in WHERE
I'm using apex 4.0 and I've currently got a SQL query that looks up a table information with SUM and includes simple math with a case statement that display OK if it tallies up or NOT okay if it doesn't in a separate row,
In apex if I use PL/SQL can I return the values specific values specifically the OK to an ITEM in apex to be used elsewhere? I've searched and cannot find anything exact likely because I'm currently ensure on the correct term.
If you have a page item called P123_FOO then you can do this in a page process:
select <whatever>
into :P123_FOO
from <whatever>;
The usual exceptions will be raised if the query returns no rows or more than one.
I have any oracle table that sometimes has valid null values is some cells. In SQL Developer it displays in the null cell as (null). This is not a problem but in a grid I have on a jsp page is also displays as (null) and I need it just to be blank. NVL does not work unless I use a space. I was wondering if there is an oracle setting or something to have valid null cells just be blank ? thank you
Modifying SQL Developer Preferences
Jeff Smith, the product manager for SQL Developer, blogged about this here, http://www.thatjeffsmith.com.
Just navigate to the SQL Developer tool bar as follows:
Preferences>Database>Advanced
and change the value in the field, "Display Null Value As", to nothing as seen here:
~~~~~~~~~~~~~~~~~~~~~~~~~~
With a jsp, one could create a method for scenarios where a column is null (to display the null as other than '(null)').
Apex beginner here. I have a view in my Oracle database of the form:
create or replace view vw_awkward_view as
select unique tab1.some_column1,
tab2.some_column1,
tab2.some_column2,
tab2.some_column3
from table_1 tab1,
table_2 tab2
WHERE ....
I need the 'unique' clause on 'tab1.some_column1' because it has many entries in its underlying table. I also need to include 'tab1.some_column1' in my view because the rest of the data doesn't make much sense without it.
In Apex, I want to create a report on this view with a form for editing it (update only). I do NOT need to edit tab1.some_column1. Only the other columns in the view need to be editable. I can normally achieve this using an 'instead-of' trigger, but this doesn't look possible when the view contains a 'distinct', 'unique' or 'group by' clause.
If I try to update a row on this view I get the following error:
ORA-02014: cannot select FOR UPDATE from view with DISTINCT, GROUP BY, etc.
How can I avoid this error? I want my 'instead-of' trigger to kick in and perform the update and I don't need to edit the column which has the 'unique' clause, so I think it should be possible to do this.
I think that you should be able to remove the "unique".
if tab2.some_column1, tab2.some_column2, tab2.some_column3 are not unique, then how do you want to update them ?
if they are unique then the whole result: tab1.some_column1, tab2.some_column1, tab2.some_column2, tab2.some_column3 is unique.
When you state in a sql query "unique" or "distinct" it's for all columns not only 'tab1.some_column1'
Hope i'm in the correct direction of your question here ;)
Your query could be achieved by doing something like:
select a.some_column1, tab2.some_column1, tab2.some_column2, tab2.some_column3
from table_2 tab2
join (select distinct some_column1 from table_1) a
on tab2.column_in_tab1 = a.some_column1
The reason you get the ORA-02014 error is because of the automatically generated ApplyMRU process. This process will attempt to lock a (the) changed row(s):
begin
for r in (select ...
from vw_awkward_view
where <your first defined PK column>= 'value for PK1'
for update nowait)
loop
null;
end loop;
end;
That's a bummer, and means you won't be able to use the generated process. You'll have to write your own process which does the updating.
For this, you'll have to use the F## arrays in apex_application.
If this sounds totally unfamiliar, take a look at:
Custom submit process, and on using the apex_application arrays.
Also, here is a how-to for apex from 2004 from Oracle itself. It still uses lots of htmldb references, but the gist of it is there.
(it might be a good idea to use the apex_item interface to build up your form, and have control over what is generated and what array it takes.)
What it comes down to is: loop over the array containing your items and do an UPDATE on your view with the submitted values.
Of course, you don't have locking this way, nor a way to prevent unnecessary updates.
Locking you can do yourself, with for example using the select for update method. You'd have to lock the correct rows in the table(s) you want to alter, before you update them. If the locking fails, then your process should fail.
As for the 'lost update' story: here you'd need to check the MD5-checksums. A checksum is generated from the editable columns in your form and put in the html-code. On submit, this checksum is then compared to a newly generated checksum from those same columns, but with values from the database at that time of submit. If the checksums differ, it means the record has changed between the page load and the page submit. Your process should fail because the record has been altered, and you don't want to have those overwritten. (if you go the apex_item way, then don't forget to include an MD5_CHECKSUM call (or MD5_HIDDEN).
Important note though: checksums generated by either using apex_item or simply the standard form functionality build up a string to be hashed. As you can see in apex_item.md5_hidden, checksums are generated using DBMS_OBFUSCATION_TOOLKIT.MD5.
You can get the checksum of the values in the DB in 2 ways: wwv_flow_item.md5 or using dbms_obfuscation.
However, what the documentation fails to mention is this: OTN Apex discussion on MD5 checksums. Pipes are added in the generated checksums! Don't forget this, or it'll blow up in your face and you'll be left wondering for days what the hell is wrong with it.
Example:
select utl_raw.cast_to_raw(dbms_obfuscation_toolkit.md5(input_string=>
"COLUMN1" ||'|'||
"COLUMN2" ||'|'||
"COLUMN5" ||'|'||
"COLUMN7" ||'|'||
"COLUMN10" ||'|'||
"COLUMN12" ||'|'||
"COLUMN14" ||
'|||||||||||||||||||||||||||||||||||||||||||'
)) md5
from some_table
To get the checksum of a row of the some_table table, where columns 1,2,5,7,10,12,14 are editable!
In the end, this is how it should be structured:
loop over array
generate a checksum for the current value of the editable columns
from the database
compare this checksum with the submitted checksum
(apex_application.g_fcs if generated) if the checksums match,
proceed with update. If not, fail process here.
lock the correct records for updating. Specify nowait, and it
locking fails, fail the process
update your view with the submitted values. Your instead-of trigger
will fire. Be sure you use correct values for your update statement so that only this one record will be updated
Don't commit inbetween. It's either all or nothing.
I almost feel like i went overboard, and it might feel like it is all a bit much, but when you know the pitfalls it's actually not so hard to pull this custom process off! It was very knowledgable for me to play with it :p
The answer by Tom is a correct way of dealing with ths issue but I think overkill for your requirements if I understand correctly.
The easiest way may be to create a form on the table you want to edit. Then have the report edit link take the user to this form which will only update the needed columns from the one table. If you need the value of the column from the other table displayed it is simple when you create the link to pass this value to the form which can contain a display only item to show this.
I am trying to insert data in an Oracle table by using ODP.NET from a C# application, but I am getting an ORA-01400 can't insert null value error for a column in which I am NOT inserting a null value.
This is the stripped down version of the parametrized SQL command I am trying to execute. It is wrapped in an OracleCommand and executed with an invokation of ExecuteNonQuery:
declare c int;
begin
select count(*) into c from "Entradas" where "Id" = :Id and nvl("AppId", 0) = nvl(:AppId, 0);
if c>0 then
update "Entradas" set
/*...a bunch of columns...*/,
"VisitaLaboral" = :VisitaLaboral,
/*...some more columns...*/
where "Id" = :Id and nvl("AppId",0) = nvl(:AppId, 0);
else
insert into "Entradas" (
/*... a bunch of columns...*/,
"VisitaLaboral",
/*...some more columns...*/
) values (
/*...a bunch of values...*/,
:VisitaLaboral,
/*...some more values...*/
);
end if;
end;
The row does not exist previously so it is the insert part of the command the one that is executed. Of course I have verified that all the column names and column value parameters are properly placed in the SQL text.
The problem is in the VisitaLaboral column. It is of type NUMBER(1,0), it does not accept NULLs, and I am trying to insert a value of 0. This is what Visual Studio displays about the associated OracleParameter immediately before the command execution:
However if I execute the command directly in Application Express (providing the values directly in the command text), it works fine and the row is inserted.
So, what is happening here? Is there a bug in the ODP.NET library, or am I doing something wrong?
Additional information:
Database is Oracle 10g Express Release 10.2.0.1.0
Oracle.DataAccess.dll version is 4.112.1.2
Using Visual Studio 2010, targeting .NET framework 4.0
Thank you in advance!
UPDATE:
Everything works fine if I use the (deprecated) System.Data.OracleClient classes instead of ODP.NET.
WTF, Oracle? No, really, WTF?
Your problem seems to be that you don't know what is actually happening in the database. The quickest solution will be to find out what happens and use that.
connect to the database
use dbms_session.set_sql_trace(true) to enable an sql trace
do your application action
disconnect from the database
find - or ask your dba - to send you the raw trace file
In the tracefile (a plain text file) find your code and see what happens when the error is raised.
It could be that a trigger fired ....
This is a DB level error message, you can be sure that the insert has null value. Is it possible to log out the sql statement generated by the ODP.NET?
Are you really really sure that you have the columns in the same order on both the insert clause and the values clause? Check your "bunch of columns" ...
Well I know nothing about ODP.net, but if there is a value in the parameter, should the precison, scale and size attributes all be zero (as they appear to be)?
We had the same problem. We solved the problem setting column property "IsNullable" to true.