Problems in porting from Oracle to Postgres

Hi!
I am facing two problems in porting from oracle to Postgres SQL.

1> There is a code in Oracle like

Type Tstate is table of number(9)
index by binary_integer;
.
........
To define a runtime table, basically it works like a array, How can it
be possible in Postgres SQL,
I have tried create temp table.... But it not works..
Is there any way to use arrays.

2> There is one function in Oracle Executesql '...........' to execute
and what i got in Postgres is Execute immediate '.........'
But it is giving error at Execute.

I will be very thankful if any one help me.

Amit
( India )