QSparqlQuery Class Reference

The QSparqlQuery class provides a means of executing and manipulating SPARQL statements. More...

List of all members.

Public Types
enum	StatementType {   SelectStatement, AskStatement, ConstructStatement, DescribeStatement,   InsertStatement, DeleteStatement }
Public Member Functions
	QSparqlQuery (const QString &query=QString(), StatementType type=SelectStatement)
	QSparqlQuery (const QSparqlQuery &other)
QSparqlQuery &	operator= (const QSparqlQuery &other)
	~QSparqlQuery ()
StatementType	type () const
void	setType (StatementType type)
QString	query () const
void	setQuery (const QString &query)
void	bindValue (const QString &placeholder, const QVariant &val)
void	bindValue (const QSparqlBinding &binding)
void	bindValues (const QSparqlResultRow &bindings)
QVariant	boundValue (const QString &placeholder) const
QMap< QString, QSparqlBinding >	boundValues () const
void	unbindValues ()
QString	preparedQueryText () const

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Detailed Description

The QSparqlQuery class provides a means of executing and manipulating SPARQL statements.

QSparqlQuery encapsulates the functionality involved in creating SPARQL queries which are executed on a QSparqlConnection.

It can also be used to execute commands specific to an RDF store which are not standard SPARQL.

To execute the QSparqlQuery, pass it to QSparqlConnection::exec().

QSparqlQuery supports binding of parameter values to placeholders; ?: and $: are used as placeholder markers.

You can retrieve the values of all the fields in a single variable (a map) using boundValues().

Approaches to Binding Values

QSparqlQuery supports replacing placeholders (marked with ?: or $:) with strings.

    QSparqlQuery nameQuery("select ?ng ?nf "
    "{ ?:contact_uri nco:nameGiven ?ng ; nco:nameFamily ?nf . } ");
    nameQuery.bindValue("contact_uri", QUrl(uri));

When replacing strings, the quotes surrounding strings are inserted automatically. Quotes (" and ') inside the strings are escaped.

See also:

QSparqlConnection, QSparqlQueryModel, QSparqlResult, QSparqlResultRow, QSparqlBinding, QVariant

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Member Enumeration Documentation

enum QSparqlQuery::StatementType

This enum contains a list of SPARQL statement (or clause) types the driver can create.

Enumerator:

SelectStatement	A SPARQL SELECT statement
AskStatement	A SPARQL ASK statement
ConstructStatement	A SPARQL CONSTRUCT statement
DescribeStatement	A SPARQL DESCRIBE statement
InsertStatement	A SPARQL INSERT statement
DeleteStatement	A SPARQL DELETE statement

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Constructor & Destructor Documentation

QSparqlQuery::QSparqlQuery	(	const QString &	query = QString(),
		StatementType	type = SelectStatement
	)			[explicit]

Constructs a QSparqlQuery object which uses the QSparqlResult result to communicate with a database.

QSparqlQuery::QSparqlQuery

(

const QSparqlQuery &

other

)

Constructs a copy of other.

QSparqlQuery::~QSparqlQuery

(

)

Destroys the object and frees any allocated resources.

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Member Function Documentation

void QSparqlQuery::bindValue	(	const QString &	placeholder,
		const QVariant &	val
	)

Set the placeholder placeholder to be bound to value val in the query. Note that the placeholder mark (?: or $:) must not be included when specifying the placeholder name.

See also:

bindValue(), boundValue() boundValues()

void QSparqlQuery::bindValue

(

const QSparqlBinding &

binding

)

Set the placeholder binding.name() to be bound to value binding.value() in the query. Note that the placeholder mark (?: or $:) must not be included when specifying the placeholder name.

void QSparqlQuery::bindValues

(

const QSparqlResultRow &

bindings

)

Iterates through the variable name - value pairs from the bindings and adds them as bindings.

QVariant QSparqlQuery::boundValue

(

const QString &

placeholder

)

const

Returns the value for the placeholder.

See also:

boundValues() bindValue()

QMap< QString, QSparqlBinding > QSparqlQuery::boundValues

(

)

const

Returns a map of the bound values.

See also:

boundValue() bindValue()

QSparqlQuery & QSparqlQuery::operator=

(

const QSparqlQuery &

other

)

Assigns other to this object.

QString QSparqlQuery::preparedQueryText

(

)

const

Replaces the placeholders with the bound values and returns the resulting query.

QString QSparqlQuery::query

(

)

const

Returns the query text without replacements.

void QSparqlQuery::setQuery

(

const QString &

query

)

Sets the query text to query. The bound placeholders are not affected.

void QSparqlQuery::setType

(

StatementType

type

)

Sets the statement type to type.

QSparqlQuery::StatementType QSparqlQuery::type

(

)

const

Returns the statement type.

void QSparqlQuery::unbindValues

(

)

Clears all bound values.