JDBC idea with special JDBC views

Hello,
I have idea for few methods in JDBC
We can add views pg_gettables, pg_getcolumns, pg_getprimarykeys
etc. and method work only connection.executeQuery("select * from
pg_gettables") (and like).Columns in view are like JDBC specification.
Now JDBC source stay unchanged and we can speedup query for view and change
with change JDBC specification
In begining schema can be null, but later we add schema support with only
change views (without change JDBC source)
We need COLUMN_SIZE and PRECISION for any view.We can make function like
format_type in postgresql source or simple view like (for getColumns) :
create view pg_getcolumns as (this is not complete view for getColumns, only
example - can be much better)
select null::varchar as "TABLE CAT",
null::varchar as "TABLE_SCHEM",
c.relname as "TABLE_NAME",a.attname as "COLUMN_NAME",
CASE t.typname
when 'int2' then 'Types.SMALLINT'
when 'int4' then 'Types.INTEGER'
when 'oid' then 'Types.INTEGER'
when 'numeric' then 'Types.NUMERIC'
else
'Types.OTHER'
end as "DATA_TYPE",
typname as "TYPE_NAME",
case typname
when 'varchar' then
case atttypmod
when -1 then null
else
(atttypmod-4)
end
when 'bpchar' then
case atttypmod
when -1 then null
else
(atttypmod-4)
end
else
attlen
end as "COLUMN_SIZE",
null::int4 as "BUFFER_LENGTH",
case typname
when 'numeric' then
case atttypmod
when -1 then null
else
(atttypmod-4) >> 16
end
when 'decimal' then
case atttypmod
when -1 then null
else
(atttypmod-4) >>16
end
end as "DECIMAL_DIGITS",
case typname
when 'numeric' then
case atttypmod
when -1 then null
else
(int4(atttypmod)-int4('4')) & int4('65535')
end
when 'decimal' then
case atttypmod
when -1 then null
else
(int4(atttypmod)-int4('4')) & int4('65535')
end
end as "NUM_PREC_RADIX"
from pg_class c,pg_catalog.pg_type t,pg_catalog.pg_attribute a
where c.oid=a.attrelid and t.oid=a.atttypid;

getColumns is like :

connection.CreateStatement().executeQuery("SELECT * " +
"FROM pg_getcolumns " +
"WHERE \"TABLE_CAT\" LIKE " + catalog==null ? "%" : catalog +
etc

Maybe is better with PreparedStatement in this method

regards
Haris Peco