ablocal_expr is a parameter of itable component of Ab Initio.ABLOCAL() is replaced by the contents of ablocal_expr.Which we can make use in parallel unloads.There are two forms of AB_LOCAL() construct, one with no arguments and one with single argument as a table name(driving table).

The use of AB_LOCAL() construct is in Some complex SQL statements contain grammar that is not recognized by the Ab Initio parser when unloading in parallel. You can use the ABLOCAL() construct in this case to prevent the Input Table component from parsing the SQL (it will get passed through to the database). It also specifies which table to use for the parallel clause.

one example is, if you want to use oracle hint in your select query at input table...u should use AB_LOCAL(table) to parse the query at Database sQL engine not by AI parser.

It is mainly used at parallel unload.

in some cases abinitio will not recognize some part of  sql statments and unable to read the table.. to avoid this we have use AB_LOCAL() and table name when ever we use clauses like WHERE condition