-- objectClass mappings: these may be viewed as structuralObjectClass, the ones that are used to decide how to build an entry
-- id a unique number identifying the objectClass
-- name the name of the objectClass; it MUST match the name of an objectClass that is loaded in slapd's schema
-- keytbl the name of the table that is referenced for the primary key of an entry
-- keycol the name of the column in "keytbl" that contains the primary key of an entry; the pair "keytbl.keycol" uniquely identifies an entry of objectClass "id"
-- create_proc a procedure to create the entry
-- delete_proc a procedure to delete the entry; it takes "keytbl.keycol" of the row to be deleted
-- expect_return a bitmap that marks whether create_proc (1) and delete_proc (2) return a value or not
-- attributeType mappings: describe how an attributeType for a certain objectClass maps to the SQL data.
-- id a unique number identifying the attribute
-- oc_map_id the value of "ldap_oc_mappings.id" that identifies the objectClass this attributeType is defined for
-- name the name of the attributeType; it MUST match the name of an attributeType that is loaded in slapd's schema
-- sel_expr the expression that is used to select this attribute (the "select <sel_expr> from ..." portion)
-- from_tbls the expression that defines the table(s) this attribute is taken from (the "select ... from <from_tbls> where ..." portion)
-- join_where the expression that defines the condition to select this attribute (the "select ... where <join_where> ..." portion)
-- add_proc a procedure to insert the attribute; it takes the value of the attribute that is added, and the "keytbl.keycol" of the entry it is associated to
-- delete_proc a procedure to delete the attribute; it takes the value of the attribute that is added, and the "keytbl.keycol" of the entry it is associated to
-- param_order a mask that marks if the "keytbl.keycol" value comes before or after the value in add_proc (1) and delete_proc (2)
-- expect_return a mask that marks whether add_proc (1) and delete_proc(2) are expected to return a value or not
-- objectClass mapping: entries that have multiple objectClass instances are listed here with the objectClass name (view them as auxiliary objectClass)
-- entry_id the "ldap_entries.id" of the entry this objectClass value must be added
-- oc_name the name of the objectClass; it MUST match the name of an objectClass that is loaded in slapd's schema