Updated November, 23 2023

Objects accessing

As we don’t know actual object types, all we really need is to know is object declared in the current scope(PL/SQL block or query block). We convert each object accessor into a function call. There are two types of object access:

• Static access- access to a property of the object that is not declared in a current scope (Package property, for example)

• Variable access - access to a property of the object that is declared in the current scope.

So for each type or package that is created, we create additional functions with a specific prefix for each object access type.

Packages

Functions names template:

<prefix>$<package_name>$<package_property>

Functions prefixes:

lbr$g - for getting properties and for functions with no arguments or with all default arguments(as they can be called without parenthesizes).

lbr$s - for setting properties value.

lbr$m - for methods accessing.

Pseudocode examples:

--Oracle
CREATE PACKAGE pack {
  fld1 integer;
  function func1();
}

--PostgreSQL
CREATE FUNCTION lbr$g$pack$fld1();  --getter
CREATE FUNCTION lbr$s$pack$fld1(integer);  --setter
CREATE FUNCTION lbr$m$pack$func1(); --method call
CREATE FUNCTION lbr$g$pack$func1(); --getter for f1 that calls f1() inside

Types

Functions names template:

<prefix>$<property_name>(<current_type_name>,...)

Functions prefixes:

lbr$j - for getting properties and for functions with no arguments or with all default arguments(as they can be called without parenthesizes).

lbr$z - for setting properties value.

Each type setter should set the value to a property of a copy of the object and return that copy.

For each part of a complex name of the setter function, we should transfer the corresponding object to which property want to set.

lbr$n - for methods accessing.

For collection types, lbr$j and lbr$z can be created without <property_name> to emulate accessing by index:

Pseudocode examples:

--Oracle
CREATE TYPE type {
  fld1 integer;
  function func1()
}

--PostgreSQL
CREATE TYPE type {
  fld1 integer;
}

CREATE FUNCTION lbr$j$fld1(type);           --getter
CREATE FUNCTION lbr$z$fld1(type, integer);  --setter
CREATE FUNCTION lbr$n$func1(type);          --method call
CREATE FUNCTION lbr$j$func1(type);          --getter for f1 that calls f1() inside

Objects accessors chains

First, we check if the start object is declared in a current scope (PL/SQL block or query block). Then we convert an accessor chain into a chain of corresponding function calls. Also, we convert each access by index into lbr$call function.