Proxy tables are the key to location transparency. A proxy table is a local table containing metadata which points to a remote or external table. The remote table is mapped to the proxy table to make it appear as if it were a local table.
There are three ways to create proxy tables:
The create table command allows the creation of new external tables with the following syntax:
create table table_name (column_list) [ [ external {table | file}] at “pathname” ]]
create table allows external object type table and file.
The create existing table command is used to map existing remote tables. It provides datatype conversion and allows the user to specify which columns are to be mapped with the following syntax:
create existing table table_name (column_list)
[ on segment_name ]
[[external {table | procedure | file}] at pathname]
create existing table allows external object type table, procedure and file.
The create proxy_table command creates proxy tables which automatically inherit all the columns, column names and datatypes of the external table using the following syntax:
create proxy_table table_name [ external type ] at pathname
create proxy table allows external object type table, file and directory.
Complete syntax for these commands are found in Chapter 3 of this book.
