Defines the columnar structure of a table. Each column has a name, data type and field size. Instances of this class may also be used to describe the field structure in records. More...

#include <TSADataDef.h>

Inheritance diagram for tsa::column_defs:

Public Member Functions
	column_defs (void)
	Constructor.

	column_defs (column_defs &&)
	Constructor.

	column_defs (const std::string &column_definition_string)
	Constructor. Initializes self according to column_definition_string.

	column_defs (const char *column_definition_string)
	Constructor. Initializes self according to column_definition_string.

	column_defs (const column_defs &)
	Copy constructor.

void	add_column (type_t column_type, const std::string &column_name, size_t length=1)
	Adds a column to self. Using this member it is possible to add columns individually without using a column-definition-string. More...

void	clear ()
	Clears the object. defined() will return false, and size() will return 0.

size_t	column_count (void) const
	Returns the number of columns in self.

bool	column_exists (const std::string column_name) const
	Returns true if a column with given name exists.

size_t	column_field_length (size_t position) const
	Returns the length, in bytes, of the column field at given ordinal position. Note that this value is only relevant for fields of type string. More...

size_t	column_field_length (const std::string &column_name) const
	Returns the length of the field with given column_name. Note that this value is only relevant for fields of type string. More...

const std::string &	column_name (size_t position) const
	Returns the name of the field at given ordinal position.

size_t	column_number (const std::string column_name) const
	Returns the index of the column with given name.

type_t	column_type (size_t position) const
	Returns the type of the column at given ordinal position.

type_t	column_type (const std::string &field_name) const
	Returns the type of the column with given column_name. More...

bool	defined (void) const
	Returns true if self is not empty (has column information).

void	from_string (const std::string &column_definition_string)
	Initializes self according to column_definition_string. More...

bool	has_pointer_field (void) const
	Returns true if self contains a column that is pointer type such as: type_t::void_ptr or type_t::object_ptr. More...

bool	is_equal (const column_defs &other)
	Returns true if self is equal, in every way, to other.

void	operator= (const column_defs &other)
	Assignment operator.

void	remove_column (const std::string &column_name)
	Removes the column with given column_name.

size_t	size (void) const
	Returns the number of columns in self.

std::string	to_string (void) const
	Returns self as a column-definition-string.

Public Member Functions inherited from tsa::object
	object (void)
	Constructor.

virtual	~object (void)
	Destructor.

const char *	class_name (void) const
	Returns the class name as returned by the 'Real Time Type Information' (RTTI) mechanism. More...

bool	has_same_class_as (const object &other) const
	Returns true if self has the same type as other object. More...

Detailed Description

Defines the columnar structure of a table. Each column has a name, data type and field size. Instances of this class may also be used to describe the field structure in records.

Note that the column structure of tables must not describe a record timestamp column. Since TS-API is built specifically for working with timeseries, a timestamp column is implicit to every tables.

The fields types are limited to the types declared by tsa::type_t with the exception of type_t::void_ptr. Supported types and corresponding type characters are :

float32 ('f' or 'F')
uint32 ('u' or 'U')
int32 ('i' or 'I')
int64 ('l' or 'L')
float64 ('d' or 'D')
boolean ('b' or 'B')
datetime ('t' or 'T')
date ('a' or 'A')
string. ('s' or 'S')

Objects of this type can be initialized by a data-definition-string. This string must provide a comma separated list of column names. Each column name must be complemented by a colon and a character corresponding to the column type. For example:

column_defs cdef = "open:D,high:D,low:D,close:D";

initializes the object with 4 fields of type float64 (double). float64 is the default type if no type information is given. So writing:

column_defs cdef = "open,high,low,close";

would have the same effect as the line above.

String Fields

When declaring a string field, it is necessary to add the maximum number of characters a string can have in addition to the type such as:

column_defs cdef = "symbol:S:10,exchange:S:20";

.

See also: object

Member Function Documentation

void tsa::column_defs::add_column	(	type_t	column_type,
		const std::string &	column_name,
		size_t	length = `1`
	)

Adds a column to self. Using this member it is possible to add columns individually without using a column-definition-string.

Parameters

column_type	Type of the column.
column_name	Name of the column.
length	The length of the fiels (max number of characters in string fields).

size_t tsa::column_defs::column_field_length ( size_t position ) const

Returns the length, in bytes, of the column field at given ordinal position. Note that this value is only relevant for fields of type string.

Parameters

position Zero-based index of the column.

Returns: A size_t.

size_t tsa::column_defs::column_field_length ( const std::string & column_name ) const

Returns the length of the field with given column_name. Note that this value is only relevant for fields of type string.

Parameters

column_name Name of the column.

Returns: A size_t.

type_t tsa::column_defs::column_type ( const std::string & field_name ) const

Returns the type of the column with given column_name.

Parameters

field_name Name of the field.

Returns: A type_t.

void tsa::column_defs::from_string ( const std::string & column_definition_string )

Initializes self according to column_definition_string.

See the class description for more information about the column_definition_string.

Parameters

column_definition_string String that defined column names, types and field size.

bool tsa::column_defs::has_pointer_field ( void ) const

Returns true if self contains a column that is pointer type such as: type_t::void_ptr or type_t::object_ptr.

Returns: bool.

Public Member Functions

Detailed Description

Member Function Documentation