Ram

Abstract syntax tree of the relational algebra machine (RAM).

Enums

BoolExp	`Not(b)`: True if `b` is false.
RamProgram	A `RamProgram` represents a compiled Datalog program.
RamStmt	`Insert(body)` executes the RelOp `body`.
RamTerm	Represents a Relational Algebra Machine (RAM) term.
RelOp	`Search(rv, relSym, relType, body)` iterates through the facts in relation `relSym`, saving them as RowVar `rv` and executes `body`.
RelSym	`RelSym(predSym, arity, den)` represents the relation of `predSym` which has arity `arity` and denotation `den`.
RowVar	`Named(id)` represents the unique identifier, `id`, of some row variable

Type Aliases

type alias FactTuple = (Facts, Facts)§ Source

FactsTuple consists of (oldFacts, newFacts), where oldFacts are given through joining a model, while newFacts are EDB facts written in the Datalog program.

type alias Facts = Map[RelSym, BPlusTree[Vector[Boxed], Boxed, Static]]§ Source

The extensible database (EDB) of a program.

type alias IndexInformation = (Indexes, IndexPositions)§ Source

The indexes to be created during program evaluation and their positions in memory.

type alias IndexPositions = Map[(RelSym, Int32), Int32]§ Source

Maps a RelSym and its place in Indexes[RelSym] to its final position in memory.

type alias Indexes = Map[RelSym, Vector[Search]]§ Source

Maps to the set of Search for a RelSym in the Datalog program. It represents the indexes that will be created for RelSym during program evaluation.

type alias Predicates = (List[RelSym], List[RelSym], Int64)§ Source

Contains a list of RelSym representing the names of the relations in the program, a list of Full RelSym and 1 + the maximal identifier of the Full RelSyms.

type alias Search = Vector[Int32]§ Source

A Search describes the order in which entries in a tuple are ordered. These are created during the index selection phase and are used by indexes to store tuples for efficient retrieval in range queries.

For example, the Datalog rule

A(x) :- B(x), C(_, _, x).

produces the search Vector#{2, 0, 1} for relation C. This means the tuples in C are ordered by the third element, then the first and finally the second. During the index selection phase, searches are collected and are expanded to describe the order of the whole tuple, i.e., the above search is collected as Vector#{2} but gets expanded to Vector#{2, 0, 1}. Thus, the final search used by an index has length exactly equal to the relation's arity.

Definitions

def arityOf(relSym: RelSym): Int32§ Source

Returns the arity of relSym.

def arityOfNonLat(relSym: RelSym): Int32§ Source

Returns the arity of the non-lattice part of relSym.

def makeFakeRelSym(predSym: PredSym): RelSym§ Source

Returns a RelSym wrapper of the predSym.

The returned RelSym is equivalent to a 'real' RelSym with respect to the Order on RelSym.

Used for accessing values in maps.

def toDenotation(relSym: RelSym): BoxedDenotation§ Source

Returns the denotation of relSym.

def toId(relSym: RelSym): Int64§ Source

Returns the identifier of relSym.