ObjectStatement< ObjectType, Columns > Class Template Reference

SQLite prepared statement wrapper. More...

#include <sqlite.h>

Classes
class	iterator
	Iterator class to allow iterating over the rows. More...

Public Types
using	value_type = ObjectType
	each row gets converted to a instance of this type

Public Member Functions
iterator	begin ()
	Iterator to the beginning.
iterator	end () const
	Iterator to the end.
	ObjectStatement (sqlite3 *db, const std::string &query, bool persistent)
	Create a statement for an existing database object.
	~ObjectStatement ()
	Clean up the statement.
template<class ... Parameters>
ObjectStatement &	execute (Parameters... parameters)
	Execute the statement, providing all necessary parameters.
bool	step ()
	Step to the next row in the result.
value_type	getRow () const
	Return the current row.

Private Attributes
sqlite3_stmt *	m_statement {nullptr}
	pointer to the statement object

Detailed Description

template<class ObjectType, class ... Columns>
class sqlite::ObjectStatement< ObjectType, Columns >

SQLite prepared statement wrapper.

This class is meant to prepare a SQLite statement where each row of the result is supposed to fill one object of type ObjectType.

Columns is the type of each of the columns in the returned data. When calling getRow() the selected columns from the current result row will be converted to the typesspecified by Columns and passed to the constructor of ObjectType and the resulting object is returned.

After calling execute one can iterate over the statement to get all rows.

ObjectStatement<TVector3, double, double, double> vectors(connection, "SELECT x,y,z from vectors");
for(auto&& tvec3: vectors.execute()) {
  tvec3.Print();
}

Warning

Be aware that you cannot iterate over this statement multiple times and should not have multiple independent iterators as the underlying sqlite statement object will change its state. One iteration over the rows per execute() call.

Definition at line 194 of file sqlite.h.

Member Typedef Documentation

value_type

using value_type = ObjectType

each row gets converted to a instance of this type

Definition at line 197 of file sqlite.h.

Constructor & Destructor Documentation

ObjectStatement()

ObjectStatement ( sqlite3 *  db, const std::string &  query, bool  persistent  )

inline

Create a statement for an existing database object.

Definition at line 238 of file sqlite.h.

    {
      detail::checkSQLiteError(sqlite3_prepare_v3(db, query.data(), query.size(), persistent ? SQLITE_PREPARE_PERSISTENT : 0,
                                                  &m_statement, nullptr), "Cannot prepare database statement: ");
      if (auto cols = sqlite3_column_count(m_statement); cols != sizeof...(Columns)) {
        throw std::runtime_error("Number of column (" + std::to_string(cols) + ") doesn't match number of template parameters (" +
                                 std::to_string(sizeof...(Columns)) + ')');
      }
    }

~ObjectStatement()

~ObjectStatement ( )

inline

Clean up the statement.

Definition at line 248 of file sqlite.h.

{ if (m_statement) sqlite3_finalize(m_statement); }

Member Function Documentation

begin()

iterator begin ( )

inline

Iterator to the beginning.

Definition at line 233 of file sqlite.h.

{ return iterator(this); }

end()

iterator end ( ) const

inline

Iterator to the end.

Definition at line 235 of file sqlite.h.

{ return iterator(); }

execute()

ObjectStatement & execute ( Parameters...  parameters )

inline

Execute the statement, providing all necessary parameters.

Definition at line 252 of file sqlite.h.

    {
      if (auto params = sqlite3_bind_parameter_count(m_statement); params != sizeof...(Parameters)) {
        throw std::runtime_error("Number of arguments (" + std::to_string(sizeof...(Parameters)) +
                                 ") doesn't match number of statement parameters (" + std::to_string(params) + ")");
      }
      sqlite3_reset(m_statement);
      auto parameter_tuple = std::make_tuple(parameters...);
      detail::visitTupleWithIndex(parameter_tuple, detail::ParameterBinder{m_statement});
      return *this;
    }

getRow()

value_type getRow ( ) const

inline

Return the current row.

Definition at line 277 of file sqlite.h.

    {
      std::tuple<Columns...> result;
      detail::visitTupleWithIndex(result, detail::ColumnFiller{m_statement});
      return std::make_from_tuple<value_type>(std::move(result));
    }

step()

bool step ( )

inline

Step to the next row in the result.

Returns

true if a new row is loaded, false if there a no more rows.

Definition at line 267 of file sqlite.h.

    {
      if (auto ret = sqlite3_step(m_statement); ret != SQLITE_ROW) {
        if (ret == SQLITE_DONE) return false;
        detail::checkSQLiteError(ret);
      }
      return true;
    }

Member Data Documentation

m_statement

sqlite3_stmt* m_statement {nullptr}

private

pointer to the statement object

Definition at line 285 of file sqlite.h.

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The documentation for this class was generated from the following file:

• framework/utilities/include/sqlite.h