Luc
We did this same upgrade some time ago and what we did was alter all the
varchar2 fields from BYTE to CHAR which then did not involve an increase in
the size field (although, of course, may actually increase the storage of
the column).
After running csscan to identify truncated or lossy columns - we then
exported those tables and then after changing the character set and
modifying the columns, deleting the data (truncating) (which involved
turning off foreign keys) and then importing the data back in.
All went quite smoothly in the end after a few practice runs!
HTH
Luke
Luc Demanche wrote:
Nigel,
If I understand correctly, I only have to change the existing column size
? Should I multiple by 4 the size of my varchar2 ? Even if the column
is not mentionned in the report of csscan ?
After that, I recompile every storedprocs, views, etc manually.
Then, I set the NLS_LENGTH_SEMANTICS=CHAR, so I don't have to worry about
the size of my varchar2 anymore ?
Thank you
Luc
On 1/10/07, Nigel Thomas <nigel_cl_thomas@xxxxxxxxx> wrote:
>
> Luc
>
>
> Q1/Q3: If you set the parameter NLS_LENGTH_SEMANTICS=CHAR then any
> ambiguous *new* column/variable definitions will be made long enough for
> characters rather than bytes. That seems a lot easier than changing every
> single table and package definition.
>
> But existing columns won't be affected, as I recall. You would need to
> MODIFY table/column definitions according (and then recompile affected
> views, dependent packages etc).
>
> You should beware of the possible implications on index key sizes (as
> the
>
> VARCHAR2 / NVARCHAR2 declarations in PL/SQL will be fixed as the
> packages are recompiled (mostly this will happen implicitly because of your
> DDL on the underlying tables - but you should check that any packages that
> aren't automatically recompiled are manually recompiled.
>
> Q2: of course Oracle limits SQL types (NOT in PL/SQL) to 4000 bytes - so
> up to 1000 * 4 byte chars (of course, most of your characters will occupy
> just 1 or 2 bytes - your exact mileage will vary depending on language). You
> can use CLOB instead, and many string functions work directly against
> 'small' CLOBS - but remember that CLOBs also have some drawbacks (LOB space
> management etc), so only convert if you are sure you have to.
>
> HTH
>
> Regards Nigel
>
>
--
Luc Demanche
Oracle DBA
(514) 867-9977
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