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    <p>Oracle uses sequences as for his identity columns, if we may say so.</p> <p>If you have set a sequence for your table primary key, you also have to write a trigger that will insert the Sequence.NextValue or so into your primary key field.</p> <p>Assuming that you are already familiar with this concept, simply query your sequence, then you will get your answer. What is very practiced in Oracle is to make yourself a function which will return an INT, then within your function, you perform your INSERT. Assuming that you have setup your trigger correctly, you will then be able to return the value of your sequence by querying it.</p> <p>Here's an instance:</p> <pre><code>CREATE TABLE my_table ( id_my_table INT PRIMARY KEY description VARCHAR2(100) NOT NULL ) CREATE SEQUENCE my_table_seq MINVALUE 1 MAXVALUE 1000 START WITH 1 INCREMENT BY 2 CACHE 5; </code></pre> <p>If you want to manage the auto-increment yourself, here's how:</p> <pre><code>INSERT INTO my_table ( id_my_table, description ) VALUES (my_table_seq.NEXTVAL, "Some description"); COMMIT; </code></pre> <p>On the other hand, if you wish not to care about the PRIMARY KEY increment, you may proceed with a trigger.</p> <pre><code>CREATE OR REPLACE TRIGGER my_table_insert_trg BEFORE INSERT ON my_table FOR EACH ROW BEGIN SELECT my_table_seq.NEXTVAL INTO :NEW.id_my_table FROM DUAL; END; </code></pre> <p>Then, when you're inserting, you simply type the INSERT statement as follows:</p> <pre><code>INSERT INTO my_table (description) VALUES ("Some other description"); COMMIT; </code></pre> <p>After an INSERT, I guess you'll want to </p> <pre><code>SELECT my_table_seq.CURRVAL </code></pre> <p>or something like this to select the actual value of your sequence.</p> <p>Here are some links to help:</p> <p><a href="http://www.orafaq.com/wiki/Sequence" rel="noreferrer">http://www.orafaq.com/wiki/Sequence</a></p> <p><a href="http://www.orafaq.com/wiki/AutoNumber_and_Identity_columns" rel="noreferrer">http://www.orafaq.com/wiki/AutoNumber_and_Identity_columns</a></p> <p>Hope this helps!</p>
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    1. POHow to get the generated id from an inserted row using ExecuteScalar?
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    1. USWill Marcouiller
    1. USWill Marcouiller
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    1. POHow to get the generated id from an inserted row using ExecuteScalar?
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    1. COHi Will, Nice, I didn't think about seq.CURRVAL. But is this save? I mean, if someone inserts a row between my two calls (insert, select)?
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      1. USandrecarlucci
    2. COTypically these kinds of operations are relative to your database connection/session to prevent just such an occurrence. I can't find it in black & white for Oracle but that's the way it works for MySQL, Access, SQL Server, etc.
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      1. USCrazy Joe Malloy
    3. COOracle will perform the inserts in a sequential manner. Once it got through the first INSERT statement and returned the new current sequence's value, it will perform the other insert. As stated by Mr. Crazy Joe Malloy, that is no matter what the way of doing it anyway. :) We must not forget that Oracle works in a transactional way. So, no NEXTVALUE will be selected from the sequence as long as the INSERT statement is not COMMITed. In anyway, if I remember correctly, there's somekind of lock somewhere (TABLE or SEQUENCE) while performing the transaction.
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      1. USWill Marcouiller
 

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