Difference between revisions of "OpenDBX/C API/odbx column count"
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__NOTOC__ | __NOTOC__ | ||
| − | + | '''Get the number of columns in the current result set''' | |
| − | + | ||
| − | + | #include <opendbx/api.h> | |
| − | odbx_result_t* '''result''' ) | + | |
| + | int '''odbx_column_count'''( | ||
| + | odbx_result_t* '''''result''''' ) | ||
== Description == | == Description == | ||
| − | Returns the number of columns which belongs to the current result set allocated by [[OpenDBX | + | 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. |
| − | The '''result''' parameter required by this function must be a valid result set returned by [[OpenDBX | + | 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. |
| − | == Return | + | == Return value == |
| − | + | [[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. | |
== Errors == | == Errors == | ||
| − | This function will also return zero if the '''result''' parameter is invalid. | + | This function will also return zero if the '''''result''''' parameter is invalid. |
== See also == | == See also == | ||
| − | * [[OpenDBX | + | * [[OpenDBX/API/odbx_column_name|odbx_column_name]]() |
| − | * [[OpenDBX | + | * [[OpenDBX/API/odbx_column_type|odbx_column_type]]() |
| − | + | * [[OpenDBX/API/odbx_result|odbx_result]]() | |
| − | + | ||
| − | + | ||
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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.
