Difference between revisions of "OpenDBX/C API/odbx column count"

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__NOTOC__
 
__NOTOC__
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'''Get the number of columns in the current result set'''
  
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  unsigned long odbx_column_count(
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  #include <opendbx/api.h>
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    odbx_result_t* result )
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= Description: =
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int '''odbx_column_count'''(
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    odbx_result_t* '''''result''''' )
  
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Returns the number of columns of the current result set allocated by [[OpenDBX_result|odbx_result()]]. The number of columns doesn't change within a result set.
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== Description ==
  
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= Parameters: =
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Returns the number of columns which belongs to the current result set allocated by [[OpenDBX/API/odbx_result|odbx_result]](). The number will never change within a result set with one notable exception: MySQL returns all outstanding rows of a previous result set first if they were not fetched completely by [[OpenDBX/API/odbx_row_fetch|odbx_row_fetch]]() before. Therefore, the column count might change in this special situation. It is strongly advised to fetch all rows of a result set before calling [[OpenDBX/API/odbx_result|odbx_result]]() again because other backends will return an error in this case.
  
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* result: Pointer to object created by [[OpenDBX_result|odbx_result()]]
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The '''''result''''' parameter required by this function must be a valid result set returned by [[OpenDBX/API/odbx_result|odbx_result]]() and must not has been feed to [[OpenDBX/API/odbx_result_finish|odbx_result_finish]]() before.
  
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= Return values: =
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== Return value ==
  
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* Number of fields returned by the last query
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[[OpenDBX/API/odbx_column_count|odbx_column_count]]() returns the number of columns/fields which are available in the current result set. The value depends on the column list being part of the SELECT query and it is zero if the query wasn't a SELECT-like query.
  
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= Errors: =
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== Errors ==
  
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* None
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This function will also return zero if the '''''result''''' parameter is invalid.
  
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== See also ==
  
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----
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* [[OpenDBX/API/odbx_column_name|odbx_column_name]]()
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Back to [[OpenDBX API|Overview]]
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* [[OpenDBX/API/odbx_column_type|odbx_column_type]]()
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* [[OpenDBX/API/odbx_result|odbx_result]]()

Latest revision as of 23:10, 28 April 2009

Get the number of columns in the current result set 

#include <opendbx/api.h>

int odbx_column_count(
    odbx_result_t* result )

Description

Returns the number of columns which belongs to the current result set allocated by odbx_result(). The number will never change within a result set with one notable exception: MySQL returns all outstanding rows of a previous result set first if they were not fetched completely by odbx_row_fetch() before. Therefore, the column count might change in this special situation. It is strongly advised to fetch all rows of a result set before calling odbx_result() again because other backends will return an error in this case.

The result parameter required by this function must be a valid result set returned by odbx_result() and must not has been feed to odbx_result_finish() before.

Return value

odbx_column_count() returns the number of columns/fields which are available in the current result set. The value depends on the column list being part of the SELECT query and it is zero if the query wasn't a SELECT-like query.

Errors

This function will also return zero if the result parameter is invalid.

See also

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