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GNOME Data Access 3.0 manual | ![]() |
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enum GdaCommandOptions; enum GdaCommandType; GdaCommand; GdaCommand* gda_command_new (const gchar *text, GdaCommandType type, GdaCommandOptions options); void gda_command_free (GdaCommand *cmd); GdaCommand* gda_command_copy (GdaCommand *cmd); const gchar* gda_command_get_text (GdaCommand *cmd); void gda_command_set_text (GdaCommand *cmd, const gchar *text); GdaCommandType gda_command_get_command_type (GdaCommand *cmd); void gda_command_set_command_type (GdaCommand *cmd, GdaCommandType type); GdaCommandOptions gda_command_get_options (GdaCommand *cmd); void gda_command_set_options (GdaCommand *cmd, GdaCommandOptions options);
The GdaCommand structure holds data needed to issue a command to the providers. Applications usually create a GdaCommand (via gda_command_new), set its properties (via the gda_command_set_* functions) and pass it over to the database using the GdaConnection functions.
One interesting thing about GdaCommand's is that they can be reused over and over. That is, applications don't need to create a command every time they want to run something on the connected database. Moreover, the ability to create command strings with placeholders allows the use of parameters to specify the values for those placeholders. Thus, an application can create a command of the form:
INSERT INTO employees VALUES (%id, %name, %address, %salary)
and reuse the same command over and over, just using different values for the placeholders.
The value for the placeholders is specified when sending the GdaCommand to a database connection, which is done via the gda_connection_execute function.
typedef enum { GDA_COMMAND_OPTION_IGNORE_ERRORS = 1, GDA_COMMAND_OPTION_STOP_ON_ERRORS = 1 << 1, GDA_COMMAND_OPTION_BAD_OPTION = 1 << 2 } GdaCommandOptions;
And OR'ed combination of GDA_COMMAND_OPTIONS_* values.
typedef enum { GDA_COMMAND_TYPE_SQL, GDA_COMMAND_TYPE_XML, GDA_COMMAND_TYPE_PROCEDURE, GDA_COMMAND_TYPE_TABLE, GDA_COMMAND_TYPE_SCHEMA, GDA_COMMAND_TYPE_INVALID } GdaCommandType;
typedef struct { gchar *text; GdaCommandType type; GdaCommandOptions options; } GdaCommand;
GdaCommand* gda_command_new (const gchar *text, GdaCommandType type, GdaCommandOptions options);
Creates a new GdaCommand from the parameters that should be freed by calling gda_command_free.
If there are conflicting options, this will set options
to
GDA_COMMAND_OPTION_DEFAULT.
|
the text of the command. |
|
a GdaCommandType value. |
|
a GdaCommandOptions value. |
Returns : |
a newly allocated GdaCommand. |
void gda_command_free (GdaCommand *cmd);
Frees the resources allocated by gda_command_new.
|
a GdaCommand. |
GdaCommand* gda_command_copy (GdaCommand *cmd);
Creates a new GdaCommand from an existing one.
|
command to get a copy from. |
Returns : |
a newly allocated GdaCommand with a copy of the data in cmd .
|
const gchar* gda_command_get_text (GdaCommand *cmd);
Gets the command text held by cmd
.
|
a GdaCommand. |
Returns : |
the command string of cmd .
|
void gda_command_set_text (GdaCommand *cmd, const gchar *text);
Sets the command text of cmd
.
|
a GdaCommand |
|
the command text. |
GdaCommandType gda_command_get_command_type (GdaCommand *cmd);
Gets the command type of cmd
.
|
a GdaCommand. |
Returns : |
the command type of cmd .
|
void gda_command_set_command_type (GdaCommand *cmd, GdaCommandType type);
Sets the command type of cmd
.
|
a GdaCommand |
|
the command type. |
GdaCommandOptions gda_command_get_options (GdaCommand *cmd);
Gets the command options of cmd
.
|
a GdaCommand. |
Returns : |
the command options of cmd .
|
void gda_command_set_options (GdaCommand *cmd, GdaCommandOptions options);
Sets the command options of cmd
. If there conflicting options, it will just
leave the value as before.
|
a GdaCommand |
|
the command options. |