Documentation

An algebraic plan is the result of constructing a graph. | The pair consists of the mapping from nodes to their respective ids | and the algres from the top node.

Union between two plans

Attach a column ResAttrName of type ATy with value AVal in all rows to table AlgNode

Project/rename certain column out of a plan

Get the current loop table

Similar to rowrank but this will assign a emph{unique} number to every row (even if two rows are equal)

Same as rownum but columns can be assigned an ordering direction

Join two plans where the columns n1 of table 1 and columns n2 of table 2 are equal.

Assign a number to each row in column ResAttrName incrementing sorted by SortInf. The numbering is not dense!

The same as eqJoin but with multiple columns.

Remove duplicate rows

Same as rank but provides a dense numbering.

Cast column AttrName to type ATy and give it the name ResAttrName afterwards.

Compute the difference between two plans.

Apply aggregate functions to a plan

Select rows where the column SelAttrName contains True.

Get's the nth element(s) of a (partitioned) table.

Construct a database table node The first argument is the emph{qualified} name of the database table. The second describes the columns in alphabetical order. The third argument describes the database keys (one table key can span over multiple columns).

Negate the boolen value in column n and store it in column r

Make cross product from two plans

Apply an operator to the element in LeftAttrName and RightAttrName, store the result in ResAttrName

Construct an empty table node with

Evaluate the graph construction computation with the current environment extended with a binding n to v.

Evaluate the graph construction computation with a differnt gamma, | and loop table. Return within he current computational context.

Get the current variable environment

Lookup a variable in the environment

Create an algebraic nat value

Create an algebraic int value

Create an algebraic boolean value

Create an algebraic double value

Create an algebraic string value

Types of algebraic values

Sorting rows in a direction

An algebraic solution is a triple consisting of the node id, a description of the database columns and all subplans

The column data type is used to represent the table structure while compiling ferry core into an algebraic plan The col column contains the column number and the type of its contents The NCol column is used to group columns that together form an element of a record , its string argument is used to represent the field name.

One table can have multiple columns

Algebraic types At this level we do not have any structural types anymore those are represented by columns. ASur is used for surrogate values that occur for nested lists.

Schema information, represents a table structure, the first element of the tuple is the column name the second its type.

Multiple keys

Graphs are constructed in a monadic environment. | The graph constructed has to be a DAG. | The reader monad provides access to the variable environment Gamma and the loop table | The variable environment is a mapping from variable names to graphnodes that represent | their compiled form. | The state monad gives access to a supply of fresh variables, and maintains a map from | nodes to node ids. When a node is inserted and an equal node (equal means, equal node | and equal child nodes) already exists in the map the node id for that already existing | node is returned. This allows maximal sharing.

Variable environemtn mapping from variables to compiled nodes.

Shorthand for the initial loop condition used by Ferry.

Evaluate the monadic graph into an algebraic plan, given a loop relation.