SQL Server to Oracle port

Question

Hi, I am investigating the feasability of porting an application
to Oracle that currently uses SQL Server as the back end database.
To that end I have installed Oracle XE and I have a several questions.
First, I guess because this is a demo, I cannot do the
"CREATE DATABASE" command, right? I just have to add tables to
the single database that is allowed on by installation? That
limitation would be removed on any other edition I assume?
Second, our current application defines data items in a way that
I think are Microsoft extensions and don't seem to be supported by
Oracle, for example, when trying this line in a CREATE TABLE
command:
FolderKey Int IDENTITY NOT NULL PRIMARY KEY,
I get an error about a missing parenthesis. I take it that
"Identity" variables (value automatically generated by the
server) are not supported? Is there an alternative way of
doing that, so I would not have to redesign the database
too much?
Further, the following line:
UserID VarChar(64) NOT NULL FOREIGN KEY REFERENCES Users(UserID)
which I thought was a standard way to define a key, also generates
an error about a missing paren. What is the correct syntax?
We also have varibles defined as "DateTime" which I guess are
not allowed? I suppose we could switch to "Date". Does anybody
have information about how Date variables are stored internally,
i.e. what I would get when I bind the variable to my C program?
Lastly, we have several variables defined as VarChar(max),
in which SQL Server allows us to store text or binary data
of length up to 2 gb. This does not work either. I guess I
have to use a BLOB or CLOB variable?
I have not yet tried to make an ODBC connection (what we
currently use to connect to SQL Server) to Oracle XE. Should
I anticipate any problems getting that to work?

Answer 1

Oracle Database XE does not allow more than one instance per server.
To define a primary key correct syntax is:
Create table summary(
Field NOT NULL PRIMARY KEY,
Or:
PRIMARY KEY constraint tabla_PK (field)
To generate the value of the primary key you must create a sequence before or after creating the table:
Create Sequence summary_seq
Start with 1
Increment by 1
Nocycle;
You can use the sequence in INSERT INTO or through a trigger:
With Insert Into:
Insert into Summary
Values (summary_seq.nextval, valkor1, value2 ,...);
With a trigger:
Create or replace Trigger BI_summary
Before Insert on SUMMARY
For each row
Begin
Select summary_seq.nextval into campoPK
From dual;
End;