Statement

Object Hierarchy:

Description:

[ CCode ( type_id = "tracker_sparql_statement_get_type ()" ) ]
[ GIR ( name = "SparqlStatement" ) ]
public abstract class Statement : Object

`TrackerSparqlStatement` represents a prepared statement for a SPARQL query.

The SPARQL query will be internally compiled into the format that is most optimal to execute the query many times. For connections created through [ctor@SparqlConnection.new] that will be a SQLite compiled statement.

The SPARQL query may contain parameterized variables expressed via the `~` prefix in the SPARQL syntax (e.g. `~var`), these may happen anywhere in the SPARQL where a literal or variable would typically happen. These parameterized variables may be mapped to arbitrary values prior to execution. The `TrackerSparqlStatement` may be reused for future queries with different values.

The argument bindings may be changed through the [method@SparqlStatement.bind_int], [method@SparqlStatement.bind_int], etc... family of functions. Those functions receive a name argument corresponding for the variable name in the SPARQL query (eg. `"var"` for `~var`) and a value to map the variable to.

Once all arguments have a value, the query may be executed through [method@SparqlStatement.execute_async] or [ method@SparqlStatement.execute].

It is possible to use any `TrackerSparqlStatement` from other threads than the one it was created from. However, binding values and executing the statement must only happen from one thread at a time. It is possible to reuse the `TrackerSparqlStatement` right after [ method@SparqlStatement.execute_async] was called, there is no need to wait for [method@SparqlStatement.execute_finish].

In some circumstances, it is possible that the query needs to be recompiled from the SPARQL source. This will happen transparently.

Namespace: Tracker.Sparql

Package: tracker-sparql-3.0

Content:

Properties:

public Connection connection { get; construct; }
The [class@SparqlConnection] the statement was created for.
public string sparql { get; construct; }
SPARQL query stored in this statement.

Creation methods:

protected Statement ()

Methods:

public void bind_boolean (string name, bool value)
Binds the boolean value to the parameterized variable given by name.
public void bind_datetime (string name, DateTime value)
Binds the [type@GLib.
public void bind_double (string name, double value)
Binds the double value to the parameterized variable given by name.
public void bind_int (string name, int64 value)
Binds the integer value to the parameterized variable given by name.
public void bind_langstring (string name, string value, string langtag)
Binds the value to the parameterized variable given by name, tagged with the language defined by langtag.
public void bind_string (string name, string value)
Binds the string value to the parameterized variable given by name.
public void clear_bindings ()
Clears all bindings.
public Cursor execute (Cancellable? cancellable = null) throws Error
Executes the `SELECT` or `ASK` SPARQL query with the currently bound values.
public async Cursor execute_async (Cancellable? cancellable = null) throws Error
Executes asynchronously the `SELECT` or `ASK` SPARQL query with the currently bound values.
public unowned Connection get_connection ()
Returns the [class@SparqlConnection] that this statement was created for.
public unowned string get_sparql ()
Returns the SPARQL string that this prepared statement holds.
public async InputStream serialize_async (SerializeFlags flags, RdfFormat format, Cancellable? cancellable = null) throws Error
Serializes a `DESCRIBE` or `CONSTRUCT` query into the given RDF format.
public bool update (Cancellable? cancellable = null) throws Error
Executes the `INSERT`/`DELETE` SPARQL query series with the currently bound values.
public async bool update_async (Cancellable? cancellable = null) throws Error
Executes asynchronously the `INSERT`/`DELETE` SPARQL query series with the currently bound values.

Inherited Members:

All known members inherited from class GLib.Object