sql - DB2, Java: Can not CREATE TABLE conditionally -

i'm trying create table within if-then-else statement in java. here i've tried far:

stmt.execute(                 "begin if (select tabname syscat.tables tabname = 'kundenkontaktdaten' , tabschema = 'grp35') null "                 + "create table kundenkontaktdaten(kunden_nr int not null primary key, twitter_id varchar(40), google_id bigint, facebook_id bigint, skype_id varchar(64), telefonnummer varchar(50));"                 + "else "                 + "delete kundenkontaktdaten; "                 + "end if;"                 + "end"); 

running 1 following exception:

db2 sql error: sqlcode=-104, sqlstate=42601, sqlerrmc=key;int not null primary;<references_spec>, driver=4.13.80 

removing not null , primary key kunden_nr returns following exception:

db2 sql error: sqlcode=-104, sqlstate=42601, sqlerrmc=<ddl-statement>, driver=4.13.80 

does has idea how handle one?

greets

most ddl statements, including create table, cannot compiled in stand-alone compound sql (what might call anonymous block). need execute dynamically:

stmt.execute(     "begin if (select tabname syscat.tables tabname = 'kundenkontaktdaten' , tabschema = 'grp35') null "   + "execute immediate 'create table kundenkontaktdaten (...)';"   + ...