MIME-Version: 1.0
From: Muhammad Ikram <mmikram@gmail.com>
Date: Fri, 3 May 2024 15:57:53 +0500
Message-ID: <CAGeimVpSjtMuq_J8bL_U3qe4ZaH78sVc35sdjZWO9sqJyLtLnA@mail.gmail.com>
Subject: Identity column data type difference in PostgreSQL and Oracle
To: PostgreSQL General <pgsql-general@lists.postgresql.org>
Content-Type: multipart/alternative; boundary="00000000000073f73606178a9822"
Archived-At: <https://www.postgresql.org/message-id/CAGeimVpSjtMuq_J8bL_U3qe4ZaH78sVc35sdjZWO9sqJyLtLnA%40mail.gmail.com>
Precedence: bulk

--00000000000073f73606178a9822
Content-Type: text/plain; charset="UTF-8"

Hello,

Tables which have an identity column in Oracle when migrated to PostgreSQL,
the data type of Identity column is changed to bigint from number by the
tools. This causes the size of column to be reduced to max value supported
by bigint which is way lower than the oracle  number max.
Secondly one has to change referencing columns data type as well.

What should be a better strategy for such transformations ?

Sample tables

CREATE TABLE Sales (
    *transaction_id* NUMBER GENERATED ALWAYS AS IDENTITY MINVALUE 1
MAXVALUE <maxvaluefornumberdatatype> INCREMENT BY 1 START WITH 1  NOCYCLE
    customer VARCHAR2(100),
    transaction_date DATE,
    store_id NUMBER
);

CREATE TABLE Sales_Details (
    *transaction_id* NUMBER,
    item VARCHAR2(100),
    quantity NUMBER,
    price NUMBER,
    CONSTRAINT fk_transaction_id FOREIGN KEY (transaction_id) REFERENCES
Sales(transaction_id)
);

--
Regards,
Muhammad Ikram

--00000000000073f73606178a9822
Content-Type: text/html; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable

<div dir=3D"ltr">Hello,=C2=A0<br><br>Tables which have an identity column i=
n Oracle when migrated to PostgreSQL, the data type of Identity column is c=
hanged to bigint from number by the tools. This causes the size of column=
=C2=A0to be reduced to max value supported by bigint which is way lower tha=
n the oracle=C2=A0 number max.<br>Secondly one has to change referencing co=
lumns data type as well.<div><br>What should be a better strategy for such =
transformations ?<br><div><br></div><div>Sample tables</div><div><br>CREATE=
 TABLE Sales (<br>=C2=A0 =C2=A0 <b>transaction_id</b> NUMBER GENERATED ALWA=
YS AS IDENTITY MINVALUE 1 MAXVALUE &lt;maxvaluefornumberdatatype&gt; INCREM=
ENT BY 1 START WITH 1 =C2=A0NOCYCLE<br>=C2=A0 =C2=A0 customer VARCHAR2(100)=
,<br>=C2=A0 =C2=A0 transaction_date DATE,<br>=C2=A0 =C2=A0 store_id NUMBER<=
br>);<br><br>CREATE TABLE Sales_Details (<br>=C2=A0 =C2=A0 <b>transaction_i=
d</b> NUMBER,<br>=C2=A0 =C2=A0 item VARCHAR2(100),<br>=C2=A0 =C2=A0 quantit=
y NUMBER,<br>=C2=A0 =C2=A0 price NUMBER,<br>=C2=A0 =C2=A0 CONSTRAINT fk_tra=
nsaction_id FOREIGN KEY (transaction_id) REFERENCES Sales(transaction_id)<b=
r>);<br><div><br></div><span class=3D"gmail_signature_prefix">--</span></di=
v><div><span class=3D"gmail_signature_prefix"></span>Regards,<br><div dir=
=3D"ltr" class=3D"gmail_signature" data-smartmail=3D"gmail_signature"><div =
dir=3D"ltr"><div>Muhammad Ikram<br><br></div></div></div></div></div></div>

--00000000000073f73606178a9822--