duckdb::QueryResult Class Reference

#include <duckdb.hpp>

Inheritance diagram for duckdb::QueryResult:

Collaboration diagram for duckdb::QueryResult:

Classes
class	QueryResultIterator
	The row-based query result iterator. Invoking the. More...
class	QueryResultRow

Public Types
using	iterator = QueryResultIterator

Public Member Functions
DUCKDB_API	QueryResult (QueryResultType type, StatementType statement_type, StatementProperties properties, vector< LogicalType > types, vector< string > names, ClientProperties client_properties)
	Creates a successful query result with the specified names and types.
DUCKDB_API	QueryResult (QueryResultType type, ErrorData error)
	Creates an unsuccessful query result with error condition.
template<class TARGET >
TARGET &	Cast ()
template<class TARGET >
const TARGET &	Cast () const
DUCKDB_API const string &	ColumnName (idx_t index) const
	Returns the name of the column for the given index.
DUCKDB_API unique_ptr< DataChunk >	Fetch ()
DUCKDB_API unique_ptr< DataChunk >	FetchRaw ()
virtual DUCKDB_API string	ToString ()=0
	Converts the QueryResult to a string.
virtual DUCKDB_API string	ToBox (ClientContext &context, const BoxRendererConfig &config)
	Converts the QueryResult to a box-rendered string.
DUCKDB_API void	Print ()
	Prints the QueryResult to the console.
DUCKDB_API bool	Equals (QueryResult &other)
bool	TryFetch (unique_ptr< DataChunk > &result, ErrorData &error)
iterator	begin ()
iterator	end ()
Public Member Functions inherited from duckdb::BaseQueryResult
DUCKDB_API	BaseQueryResult (QueryResultType type, StatementType statement_type, StatementProperties properties, vector< LogicalType > types, vector< string > names)
	Creates a successful query result with the specified names and types.
DUCKDB_API	BaseQueryResult (QueryResultType type, ErrorData error)
	Creates an unsuccessful query result with error condition.
DUCKDB_API void	ThrowError (const string &prepended_message="") const
DUCKDB_API void	SetError (ErrorData error)
DUCKDB_API bool	HasError () const
DUCKDB_API const ExceptionType &	GetErrorType () const
DUCKDB_API const std::string &	GetError () const
DUCKDB_API ErrorData &	GetErrorObject ()
DUCKDB_API idx_t	ColumnCount ()

Static Public Member Functions
static void	DeduplicateColumns (vector< string > &names)
	Deduplicate column names for interop with external libraries.

Public Attributes
ClientProperties	client_properties
	Properties from the client context.
unique_ptr< QueryResult >	next
	The next result (if any)
Public Attributes inherited from duckdb::BaseQueryResult
QueryResultType	type
	The type of the result (MATERIALIZED or STREAMING)
StatementType	statement_type
	The type of the statement that created this result.
StatementProperties	properties
	Properties of the statement.
vector< LogicalType >	types
	The SQL types of the result.
vector< string >	names
	The names of the result.

Protected Member Functions
virtual DUCKDB_API unique_ptr< DataChunk >	FetchInternal ()=0
DUCKDB_API string	HeaderToString ()

Private Member Functions
	QueryResult (const QueryResult &)=delete

Additional Inherited Members
Protected Attributes inherited from duckdb::BaseQueryResult
bool	success
	Whether or not execution was successful.
ErrorData	error
	The error (in case execution was not successful)

Detailed Description

The QueryResult object holds the result of a query. It can either be a MaterializedQueryResult, in which case the result contains the entire result set, or a StreamQueryResult in which case the Fetch method can be called to incrementally fetch data from the database.

Member Function Documentation

Cast() [1/2]

template<class TARGET >

TARGET & duckdb::QueryResult::Cast ( )

inline

                   {
        if (type != TARGET::TYPE) {
            throw InternalException("Failed to cast query result to type - query result type mismatch");
        }
        return reinterpret_cast<TARGET &>(*this);
    }

Cast() [2/2]

template<class TARGET >

const TARGET & duckdb::QueryResult::Cast ( ) const

inline

                               {
        if (type != TARGET::TYPE) {
            throw InternalException("Failed to cast query result to type - query result type mismatch");
        }
        return reinterpret_cast<const TARGET &>(*this);
    }

Fetch()

DUCKDB_API unique_ptr< DataChunk > duckdb::QueryResult::Fetch

(

)

Fetches a DataChunk of normalized (flat) vectors from the query result. Returns nullptr if there are no more results to fetch.

FetchRaw()

DUCKDB_API unique_ptr< DataChunk > duckdb::QueryResult::FetchRaw

(

)

Fetches a DataChunk from the query result. The vectors are not normalized and hence any vector types can be returned.

ToString()

virtual DUCKDB_API string duckdb::QueryResult::ToString ( )

pure virtual

Converts the QueryResult to a string.

Implemented in duckdb::ArrowQueryResult, duckdb::MaterializedQueryResult, and duckdb::StreamQueryResult.

ToBox()

virtual DUCKDB_API string duckdb::QueryResult::ToBox ( ClientContext &  context, const BoxRendererConfig &  config  )

virtual

Converts the QueryResult to a box-rendered string.

Reimplemented in duckdb::MaterializedQueryResult.

Equals()

DUCKDB_API bool duckdb::QueryResult::Equals

(

QueryResult &

other

)

Returns true if the two results are identical; false otherwise. Note that this method is destructive; it calls Fetch() until both results are exhausted. The data in the results will be lost.

TryFetch()

bool duckdb::QueryResult::TryFetch ( unique_ptr< DataChunk > &  result, ErrorData &  error  )

inline

                                                                   {
        try {
            result = Fetch();
            return success;
        } catch (std::exception &ex) {
            error = ErrorData(ex);
            return false;
        } catch (...) {
            error = ErrorData("Unknown error in Fetch");
            return false;
        }
    }

begin()

iterator duckdb::QueryResult::begin ( )

inline

                     { // NOLINT: match stl API
        return QueryResultIterator(this);
    }

end()

iterator duckdb::QueryResult::end ( )

inline

                   { // NOLINT: match stl API
        return QueryResultIterator(nullptr);
    }

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

• external/duckdb/duckdb.hpp