odbx_set_option - Man Page
Change behaviour of the database backend
Synopsis
#include <opendbx/api.h>
int
odbx_set_option (odbx_t*
handle, unsigned int option, void* value);
Description
Changes the value of the specified option in the backend module or the native database library associated to handle by odbx_init(). Before trying to set an option, it should be tested with odbx_get_option() first to ensure that it is supported by the backend. Almost all options need to be set before connecting to the database server using odbx_bind() to take any effect.
The first parameter handle
is the connection object created and returned by odbx_init() which becomes invalid as soon as it was supplied to odbx_finish().
There are several option
values defined as named constants in the odbx.h header file. The available options whose values can be changed are:
- ODBX_OPT_TLS
Use encryption to transmit all data securely over the network via SSL or TLS. This option can be set to
ODBX_TLS_NEVER
(the default value) to prevent encrpytion,ODBX_TLS_ALWAYS
to enforce encryption and to fail if it can't be used between the client library and the server orODBX_TLS_TRY
to use encryption if possible with the option to fall back to a connection which isn't encrypted.- ODBX_OPT_MULTI_STATEMENTS
Enables the database server to accept multiple statements in one query string sent via odbx_query() if the value of value is set to
ODBX_ENABLE
. Although, it might be possible to disable it by setting it toODBX_DISABLE
.- ODBX_OPT_PAGED_RESULTS
All database servers and client libraries are able to transfer the records row by row. Some of them can also transfer multiple rows or even all at once to minimize server load, network traffic and latency. The downside of this is an increased memory consumption. If paged results are supported by the backend, passing positive values will fetch the specified number of records at once from the database server. The value of zero ("0") is special in this case because it asks the backend module to retrieve all records at once
- ODBX_OPT_COMPRESS
Enable compressed network traffic between database client and server. This can maximize the throughput if the network is the bottleneck. Pass an integer variable with
ODBX_ENABLE
to enable compression or withODBX_DISABLE
to disable it for this connection- ODBX_OPT_MODE
Some database servers support different modes of operation, e.g. modes for compliance to other SQL implementations or completely different query languages. This option is available since OpenDBX 1.1.4.
value
must point to a zero terminated string and for a detailed description of the MySQL modes look at their website
If not stated otherwise, the type of the variable passed to the third parameter value
must be an integer pointer. Its values should be in the range specified by the option being changed.
Return Value
odbx_set_option() returns ODBX_ERR_SUCCESS
, or an error code whose value is less than zero if one of the operations couldn't be completed successfully. Possible error codes are listed in the error section and they can be feed to odbx_error() and odbx_error_type() to get further details.
Errors
- -ODBX_ERR_PARAM
One of the supplied parameters is invalid or is NULL and this isn't allowed in the used backend module or in the native database client library
- -ODBX_ERR_OPTION
The value passed to the
option
parameter isn't one of the values listed in this manual. The content ofvalue
remains unchanged if this error occurs- -ODBX_ERR_OPTRO
The option isn't intended for being changed and could only be read via odbx_get_option()
- -ODBX_ERR_OPTWR
Setting the option failed for various reasons. It's most likely that the value passed via
value
didn't match the range of values expected by the backend or the native database library
See Also
odbx_bind(), odbx_error(), odbx_get_option()
Referenced By
odbx_get_option(3), odbx_init(3).