Database.HSparql.QueryGenerator

The query generator DSL for SPARQL, used when connecting to remote endpoints.

Creating Queries

createSelectQuery :: Query SelectQuery -> String

Execute a 'Select Query' action, returning the String representation of the query.

createConstructQuery :: Query ConstructQuery -> String

Execute a 'Construct Query' action, returning the String representation of the query.

createAskQuery :: Query AskQuery -> String

Execute a 'Ask Query' action, returning the String representation of the query.

createUpdateQuery :: Query UpdateQuery -> String

Execute a 'Update Query' action, returning the String representation of the query.

createDescribeQuery :: Query DescribeQuery -> String

Execute a 'Describe Query' action, returning the String representation of the query.

Query Actions

prefix :: Text -> IRIRef -> Query Prefix

Add a prefix to the query, given an IRI reference, and return it.

var :: Query Variable

Create and return a variable to the query, usable in later expressions.

triple :: (TermLike a, TermLike b, TermLike c) => a -> b -> c -> Query Pattern

Restrict the query to only results for which values match constants in this triple, or for which the variables can be bound.

constructTriple :: (TermLike a, TermLike b, TermLike c) => a -> b -> c -> Query Pattern

askTriple :: (TermLike a, TermLike b, TermLike c) => a -> b -> c -> Query Pattern

updateTriple :: (TermLike a, TermLike b, TermLike c) => a -> b -> c -> Query Pattern

describeIRI :: IRIRef -> Query IRIRef

optional :: Query a -> Query Pattern

Add optional constraints on matches. Variable bindings within the optional action are lost, so variables must always be defined prior to opening the optional block.

union :: Query a -> Query b -> Query Pattern

Add a union structure to the query pattern. As with optional blocks, variables must be defined prior to the opening of any block.

filterExpr :: TermLike a => a -> Query Pattern

Restrict results to only those for which the given expression is true.

Duplicate handling

distinct :: Query Duplicates

Set duplicate handling to Distinct. By default, there are no reductions.

reduced :: Query Duplicates

Set duplicate handling to Reduced. By default, there are no reductions.

Limit handling

limit :: Int -> Query Limit

Set limit handling to the given value. By default, there are no limits. Note: negative numbers cause no query results to be returned.

Order handling

orderNext :: TermLike a => a -> Query ()

Alias of orderNextAsc.

orderNextAsc :: TermLike a => a -> Query ()

Order the results, after any previous ordering, based on the term, in ascending order.

orderNextDesc :: TermLike a => a -> Query ()

Order the results, after any previous ordering, based on the term, in descending order.

Auxiliary

(.:.) :: Prefix -> Text -> IRIRef

Form a Node, with the Prefix and reference name.

iriRef :: Text -> IRIRef

Term Manipulation

Operations

(.+.) :: (TermLike a, TermLike b) => a -> b -> Expr

Add two terms.

(.-.) :: (TermLike a, TermLike b) => a -> b -> Expr

Find the difference between two terms.

(.*.) :: (TermLike a, TermLike b) => a -> b -> Expr

Multiply two terms.

(./.) :: (TermLike a, TermLike b) => a -> b -> Expr

Divide two terms.

Relations

(.==.) :: (TermLike a, TermLike b) => a -> b -> Expr

Create an expression which tests the relationship of the two operands, evaluating their equivalence.

(.!=.) :: (TermLike a, TermLike b) => a -> b -> Expr

Create an expression which tests the relationship of the two operands, evaluating their equivalence.

(.<.) :: (TermLike a, TermLike b) => a -> b -> Expr

Create an expression which tests the relationship of the two operands, evaluating their relative value.

(.>.) :: (TermLike a, TermLike b) => a -> b -> Expr

Create an expression which tests the relationship of the two operands, evaluating their relative value.

(.<=.) :: (TermLike a, TermLike b) => a -> b -> Expr

Create an expression which tests the relationship of the two operands, evaluating their relative value.

(.>=.) :: (TermLike a, TermLike b) => a -> b -> Expr

Create an expression which tests the relationship of the two operands, evaluating their relative value.

Negation

notExpr :: TermLike a => a -> Expr

Negate any term-like expression, for use, e.g., in filtering.

Builtin Functions

str :: BuiltinFunc1

lang :: BuiltinFunc1

langMatches :: BuiltinFunc2

datatype :: BuiltinFunc1

bound :: Variable -> Expr

sameTerm :: BuiltinFunc2

isIRI :: BuiltinFunc1

isURI :: BuiltinFunc1

isBlank :: BuiltinFunc1

isLiteral :: BuiltinFunc1

regex :: BuiltinFunc2

Printing Queries

qshow :: QueryShow a => a -> String

Convert most query-related types to a String, most importantly QueryDatas.

Types

type Query a = State QueryData a

The State monad applied to QueryData.

data Variable

data VarOrNode

Enables programmatic construction of triples where it is not known in advance which parts of the triple will be variables and which will be Nodes.

Constructors

Var' Variable

RDFNode Node

data Pattern

data SelectQuery

Constructors

SelectQuery

Fields

queryVars :: [Variable]

data ConstructQuery

Constructors

ConstructQuery

Fields

queryConstructs :: [Pattern]

data AskQuery

Constructors

AskQuery

Fields

queryAsk :: [Pattern]

data UpdateQuery

Constructors

UpdateQuery

Fields

queryUpdate :: [Pattern]

data DescribeQuery

Constructors

DescribeQuery

Fields

queryDescribe :: IRIRef