ERROR [22P02] ERROR: invalid input syntax for integer: ""; - sql

Question

Never seen such error:
ERROR [22P02] ERROR: invalid input syntax for integer: ""; Error while executing the query
Creating table:
Public Function PrimkCreate(ByVal myPrimkTable As String, ByVal nCon As OdbcConnection) As Integer
Dim ans As Integer
Dim cCommand As OdbcCommand = New OdbcCommand("CREATE TABLE IF NOT EXISTS " + myPrimkTable + "(" & _
"prm_id int NOT NULL, " & _
"pkni text, " & _
"pdatum text, " & _
"pdatumnaplate text, " & _
"pdanaodgode int, " & _
"puldok text, " & _
"puldokbroj text, " & _
"pdatumk text, " & _
"pvrijemek text, " & _
"pdobid int, " & _
"pdoboib text, " & _
"pnabc double precision, " & _
"purab double precision, " & _
"ppdv double precision, " & _
"ppnak double precision, " & _
"pprodc double precision, " & _
"pvrstaprimke int, " & _
"pzapisniktekst text, " & _
"prez text, " & _
"CONSTRAINT " & myPrimkTable & "_pkey PRIMARY KEY(prm_id))", nCon)
ans = cCommand.ExecuteNonQuery()
cCommand.Dispose()
Return ans
End Function
Update code:
Public Function update_LPrimk(ByRef primk As Integer, ByVal mCon As OdbcConnection) As Integer
Dim retval As Integer
Dim uCmd As OdbcCommand = New OdbcCommand("UPDATE " & myPrimkTable & " SET " & _
"prm_id=" & primk & ", " & _
"pkni='" & prm.pKni & "', " & _
"pdatum='" & prm.pDatum & "', " & _
"pdatumnaplate='" & prm.pDatumNaplate & "', " & _
"pdanaodgode=" & prm.pDanaodgode & ", " & _
"puldok='" & prm.pUlDok & "', " & _
"puldokbroj='" & prm.pUlDokBroj & "', " & _
"pdatumk='" & prm.pDatumk & "', " & _
"pvrijemek='" & prm.pVrijemek & "', " & _
"pdobid='" & prm.pDobID & "', " & _
"pdoboib='" & prm.pDobOib & "', " & _
"pnabc='" & Replace(prm.pNabc.ToString, ",", ".") & "', " & _
"purab='" & Replace(prm.pURab.ToString, ",", ".") & "', " & _
"ppdv='" & Replace(prm.pPdv.ToString, ",", ".") & "', " & _
"ppnak='" & Replace(prm.pPnak.ToString, ",", ".") & "', " & _
"pprodc='" & Replace(prm.pProdc.ToString, ",", ".") & "', " & _
"pvrstaprimke=" & prm.pVrstaPrimke & ", " & _
"pzapisniktekst='" & prm.pZapisnikTekst & "', " & _
"prez='" & prm.pRez & "' " & _
"WHERE prm_id=" + primk.ToString, mCon)
retval = uCmd.ExecuteNonQuery()
uCmd.Dispose()
Return retval
End Function
Query looks exactly like this:
UPDATE primke SET prm_id=1, pkni='U', pdatum='07.01.2013', pdatumnaplate='10.01.2013',
pdanaodgode=3, puldok='ghkzug gugug', puldokbroj='jkhk', pdatumk='', pvrijemek='',
pdobid='', pdoboib='', pnabc='0', purab='0', ppdv='0', ppnak='0', pprodc='0',
pvrstaprimke=0, pzapisniktekst='', prez='' WHERE prm_id=1
I have many tables where I run similar commands but have never seen such an error.
What might be the problem?

Answer 1

I would advice to read the chapter Constants in the manual. It's a brief and informative read.
The cause for the error message is that '' is an empty string that has no representation in a numeric type like integer.
#a_horse_with_no_name: To be precise, '0' is a string constant to PostgreSQL that can be cast to integer just as well as it can be cast to text, only text is the default for string constants. Consider this demo:
CREATE TEMP TABLE t (i int);
INSERT INTO t VALUES (1);
INSERT INTO t VALUES ('2'); -- single row inserts to make sure ..
INSERT INTO t VALUES ('3'::int); -- .. type is not coerced to type
INSERT INTO t VALUES (4::bigint); -- .. of first row by VALUES expression.
INSERT INTO t VALUES (5::numeric);
INSERT INTO t VALUES (6);
UPDATE t SET i = '0' WHERE i = '6';
SELECT * FROM t;
SQL Fiddle.