Hello,

first of all, "Thank you for your timely responses."

@Steven
On your advice I tried to change the field length with the SQL Management Studio. But it failed with the following error message:
"You are not allowed to save changes. The changes made require deleting and recreating the following tables. You have either made changes to a table that cannot be recreated or you have checked the 'Prevent saving changes that require recreation of the table' option.".
I googled the error message and found the tip to make the changes using SQL Script Language instead of Management Studio. So I created the following script:

Code:
use database
go

ALTER TABLE person
Old column PLZ_Strasse char(10);
But again I got a lot of error messages:

Code:
Message 5074, level 16, status 1, line 4
Object "GGFuncAdresseKomplettMitUnbekanntVerzogenKennzeichnung" depends on column "PLZ_Strasse".
Message 5074, level 16, status 1, line 4
Object "GGFuncAdresseKomplett" depends on column "PLZ_Strasse".
Message 5074, level 16, status 1, line 4
Object "GGFuncLocality" is dependent on column "PLZ_Strasse".
Message 5074, level 16, status 1, line 4
Object "ReferenzTest2SparMit3Tabellen" depends on column "PLZ_Strasse".
Message 5074, level 16, status 1, line 4
Object "ReferenzTest1SparMit3Tabellen" depends on column "PLZ_Strasse".
Message 5074, level 16, status 1, line 4
Index "person011" depends on column "PLZ_Strasse".
Message 4922, level 16, status 9, line 4
Error with ALTER TABLE ALTER COLUMN PLZ_Strasse, because at least one object accesses this column.
Now I slowly have no idea what to do.

The configuration of the database is the same as the "SQL Database Conversion Wizard" created the tables. I have not changed anything there.
I just added a few scalar value functions and a few SQL views.

The only thing I noticed earlier is the field option of all columns with "not zero". This does not seem to be standard in most sample SQL databases. Research has shown that this option seems to require deleting and re-creating the table when changes are made.