Consistency of sequence.curval

Question

Hi Folks,
I have a Table llike this (simplified example):
CREATE SEQUENCE tab1_seq
  START WITH 1
  INCREMENT BY 1
  MAXVALUE 99999999999999
  NOCYCLE
  CACHE 20
CREATE TABLE tab1 (
  id NUMBER(14) PRIMARY KEY,
  name VARCHAR2(16) NOT NULL,
  val1 NUMBER,
  val2 NUMBER,
  val3 NUMBER
CREATE OR REPLACE
PROCEDURE helpProc RETURN INTEGER AS
      currentval NUMBER;
BEGIN
        SELECT tab1_seq.CURRVAL INTO currentval FROM dual;
        RETURN currentval;
END;From a C-Program via Oracleinstantcllient-Library I perform the following transaction ...
(Using, OCIStmtPrepare, OCIBind*, OCIStmtExecute, .. same for other inserts/updates ..., at least OCITransCommit)
INSERT INTO tab1 (id,name) VALUES (tab1_seq.NEXTVAL, 'newdata45');
UPDATE tab1 SET val1=753.874 WHERE id=helpProc();
UPDATE tab1 SET val2=3.45678 WHERE id=helpProc();
UPDATE tab1 SET val3=0.987 WHERE id=helpProc();
-- actually there are N update staements
COMMIT;I know - that helpProc() isn't needed (also I can do it as subselect from dual) - but thats the way it implemented here (not from me, thats why I'm working on it). The mainquestion is if this is a safe way?! I can imagine that Oracle uses a kind of rowlocking and if there is another row inserted during this transaction executes the helpProc() or .currval returns not the id as it expected here. Or maybe related to the sequence cache?!
Background: Actually there are more than 3 values, let's say 50. And only N valus are known and have to been inserted. So I can find a safe efficient solution to do that in a way like it described above or I parse/compute a single insert statement inside of the c-programm.
Thanks for help!
Regards!

Answer 1

And you are sure about it's ONE session for the ocifunctions order I mentioned?
OCIHandleAlloc
OCIStmtPrepare (Prepareing the INSERT Query)
OCIBindByPos (Binding values)
OCIStmtExecute (Execute this query)
--> how does oracle know that teh session isn't ended at this point?
N-times:
OCIHandleAlloc
OCIStmtPrepare (Prepareing the UPDATE Query)
OCIBindByPos (Binding values)
OCIStmtExecute (Execute this query)
At the end:
OCITransCommit
I'm not sure if that builds an transaction which data become valid after commit only. ?!
Regards.