What is LDAP#LDAP or Lightweight Directory Access Protocol is a set of LDAP Protocol Exchanges that defines the method by which data is accessed.
Necessarily, it also defines and describes how data is represented in the directory service (the Data Model or DIT).
Finally, it defines how data is loaded into (imported) and saved from (exported) a directory service (using LDIF). LDAP does not define how data is stored or manipulated. Data storage is an 'automagic' process as far as the standard is concerned.
For another good over view of LDAP try http://www.zytrax.com/books/ldap/ NOTE: Even if you are using eDirectory vs OpenLDAP as referenced in the article, but most of the the LDAP references should be valid across LDAP Server Implementations.LDAP Message are transmitted on the wire as an single integer which is one of the reasons LDAP is "Lightweight".
In other words, LDAP Protocol Exchanges define everything you can do with LDAP and they must be performed individually. (i.e. you can NOT perform a modify and search in the same operation).Comparing LDAP and SQL is a common discussion, it is really comparing Apples and Oranges.