1. A semantic relational database, comprising: a phrase registry data store of definitions recorded in a tangible non-transitory computer readable medium, wherein the phrase registry data store stores phrase definitions that include word phrase definitions and sentence phrase definitions, and the word phrase definitions include data entity type phrase definitions and relationship type phrase definitions; a sentence data structure recorded in the computer readable medium, wherein said sentence data structure stores sentences composed of three or more of the phrase definitions according to constraints, wherein the sentences are instances of relationships between two of the phrase definitions, the relationships are defined by the relationship type phrase definitions, and the constraints permit at least one of the relationship type phrase definitions to define a relationship between the sentence phrase definition and another of the phrase definitions; at least two data handlers recorded in the computer readable medium that syntactically traverse sentences of said sentence data structure, including at least one sentence that refers to at least one other sentence by containing a sentence phrase definition for the other sentence, and report word phrases of relationships defined in the sentences; and an index and retrieval system receiving at least one query phrase definition from the user and processing the query phrase definition by accessing the computer readable medium and employing a sentence data handler, contingent on the query phrase definition matching a phrase definition of the sentence at least partly composed of the sentence phrase definition for the other sentence, to retrieve the sentence and the other sentence and to syntactically traverse the sentence and the other sentence into an ordered representation of at least two relationships defined by those two sentences, and by employing a word phrase data handler to report to the user data entities of the two sentences in an order determined by the ordered representation.