PL/pgSQL Copy data from one table to another

On Wed, Feb 5, 2014 at 7:53 AM, George Ant <g.antonopoulos000@gmail.com>wrote:

Hey Guys,

I am trying to copy data from one table to another using plpgsql. The two
tables have different structure cause the new one is object-table. My
function is this :

CREATE OR REPLACE FUNCTION copy_customers() RETURNS integer as $BODY$
DECLARE
idcounter integer := 1;
firstname text;
lastname text;
address1 text;
address2 text;
city text;
state text;
zip text;
country text;
region text;
BEGIN
FOR idcounter In 1..20000
LOOP

-- Add the values into the variables.
SELECT

"FirstName","LastName","Address1","Address2","City","State","Zip","Country","Region"
INTO firstname,
lastname,address1,address2,city,state,zip,country,region
FROM "Customers"
WHERE "CustomerId" = idcounter;

--Insert the variables to the new table.
INSERT INTO "Customers_object_table" (customerid , firstname,
lastname,
address)

VALUES(idcounter,firstname,lastname,(address1,address2,city,state,zip,country,region));
END Loop;

return 1;
END;
$BODY$
LANGUAGE plpgsql;

This function is working fine, but the problem is that the table
"Customers"
has more than 20 columns, so the code is ugly and unmaintainable. Also I
want to do the same job for 10 more tables.

Can somebody help me to change this function in a way that I won't have to
declare the columns?

Notice that the destination-tables are object tables and can be different
than the old tables, so I am not sure if what I ask is possible.

Kind Regards,
George Ant

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I assume you created a composite type (addresstype) in
Customers_object_table.

CREATE OR REPLACE FUNCTION copy_customers() RETURNS integer as $BODY$
BEGIN

INSERT INTO Customers_object_table (customerid, firstname, lastname,
address)
SELECT c.customerid, c.firstname, c.lastname, (c.address1, c.address2,
c.city, c.zip, c.country, c.region)::addresstype
FROM Customers c
WHERE c.customerid >= 1 AND c.customerid <= 20000;

RETURN 1;
END
$BODY$
LANGUAGE plpgsql;

On 2014-02-05 10:36, ChoonSoo Park wrote:

On Wed, Feb 5, 2014 at 7:53 AM, George Ant
<g.antonopoulos000@gmail.com <mailto:g.antonopoulos000@gmail.com>> wrote:

Hey Guys,

I am trying to copy data from one table to another using plpgsql.
The two
tables have different structure cause the new one is object-table. My
function is this :

CREATE OR REPLACE FUNCTION copy_customers() RETURNS integer as $BODY$
DECLARE
idcounter integer := 1;
firstname text;
lastname text;
address1 text;
address2 text;
city text;
state text;
zip text;
country text;
region text;
BEGIN
FOR idcounter In 1..20000
LOOP

-- Add the values into the variables.
SELECT
"FirstName","LastName","Address1","Address2","City","State","Zip","Country","Region"
INTO firstname,
lastname,address1,address2,city,state,zip,country,region
FROM "Customers"
WHERE "CustomerId" = idcounter;

--Insert the variables to the new table.
INSERT INTO "Customers_object_table" (customerid ,
firstname, lastname,
address)
VALUES(idcounter,firstname,lastname,(address1,address2,city,state,zip,country,region));
END Loop;

return 1;
END;
$BODY$
LANGUAGE plpgsql;

This function is working fine, but the problem is that the table
"Customers"
has more than 20 columns, so the code is ugly and unmaintainable.
Also I
want to do the same job for 10 more tables.

Can somebody help me to change this function in a way that I won't
have to
declare the columns?

Notice that the destination-tables are object tables and can be
different
than the old tables, so I am not sure if what I ask is possible.

Kind Regards,
George Ant

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I assume you created a composite type (addresstype) in
Customers_object_table.

CREATE OR REPLACE FUNCTION copy_customers() RETURNS integer as $BODY$
BEGIN

INSERT INTO Customers_object_table (customerid, firstname,
lastname, address)
SELECT c.customerid, c.firstname, c.lastname, (c.address1,
c.address2, c.city, c.zip, c.country, c.region)::addresstype
FROM Customers c
WHERE c.customerid >= 1 AND c.customerid <= 20000;

RETURN 1;
END
$BODY$
LANGUAGE plpgsql;

There's also no need for pgsql at that point - a straight up sql
function would suffice.

Hey Guys,

Thank you for your replies! Your suggestions worked fine!! :) Also my code
looks a lot cleaner now!

Kind Regards,
George Ant.

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George Ant wrote

Hey Guys,

Thank you for your replies! Your suggestions worked fine!! :) Also my code
looks a lot cleaner now!

Kind Regards,
George Ant.

Have you considered just creating a view, or even retrieval functions, the
generate these "object forms" on the fly instead of altering your database
schema? Using arrays for master-detail relationships is typically
considered wrong and is definitely non-relational. Your application should
not dictate schema design to this level generally but instead you should add
an O-R layer where needed.

David J.

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