## GdaEntity

GdaEntity — Interface to represent a generic entity (for tables, views or queries)

## Synopsis

                        GdaEntity;
    gboolean            gda_entity_has_field                (GdaEntity *iface,
                                                             GdaEntityField *field);
    GSList*             gda_entity_get_fields               (GdaEntity *iface);
    gint                gda_entity_get_n_fields             (GdaEntity *iface);
    GdaEntityField*     gda_entity_get_field_by_name        (GdaEntity *iface,
                                                             const gchar *name);
    GdaEntityField*     gda_entity_get_field_by_xml_id      (GdaEntity *iface,
                                                             const gchar *xml_id);
    GdaEntityField*     gda_entity_get_field_by_index       (GdaEntity *iface,
                                                             gint index);
    gint                gda_entity_get_field_index          (GdaEntity *iface,
                                                             GdaEntityField *field);
    void                gda_entity_add_field                (GdaEntity *iface,
                                                             GdaEntityField *field);
    void                gda_entity_add_field_before         (GdaEntity *iface,
                                                             GdaEntityField *field,
                                                             GdaEntityField *field_before);
    void                gda_entity_swap_fields              (GdaEntity *iface,
                                                             GdaEntityField *field1,
                                                             GdaEntityField *field2);
    void                gda_entity_remove_field             (GdaEntity *iface,
                                                             GdaEntityField *field);
    gboolean            gda_entity_is_writable              (GdaEntity *iface);

## Object Hierarchy

      GInterface
       +----GdaEntity

## Prerequisites

GdaEntity requires GdaObject.

## Known Implementations

GdaEntity is implemented by GdaDictTable and GdaQuery.

## Signals

      "field-added"                                    : Run First
      "field-removed"                                  : Run First
      "field-updated"                                  : Run First
      "fields-order-changed"                           : Run First

## Description

## Details

### GdaEntity

    typedef struct _GdaEntity GdaEntity;

### gda_entity_has_field ()

    gboolean            gda_entity_has_field                (GdaEntity *iface,
                                                             GdaEntityField *field);

Tells if `field` belongs to the `iface` entity

`iface` : | an object implementing the GdaEntity interface
`field` : | an object implementing the GdaEntityField interface
Returns : | TRUE if `field` belongs to the `iface` entity

### gda_entity_get_fields ()

    GSList*             gda_entity_get_fields               (GdaEntity *iface);

Get a new list containing all the GdaEntityField objects held within the object implementing the GdaEntity interface.

The returned list nodes are in the order in which the fields are within the entity.

`iface` : | an object implementing the GdaEntity interface
Returns : | the new list.

### gda_entity_get_n_fields ()

    gint                gda_entity_get_n_fields             (GdaEntity *iface);

Get the number of fields in `iface`

`iface` : | an object implementing the GdaEntity interface
Returns : | the number of fields, or -1 if an error occurred

### gda_entity_get_field_by_name ()

    GdaEntityField*     gda_entity_get_field_by_name        (GdaEntity *iface,
                                                             const gchar *name);

Get a GdaEntityField using its name. The notion of "field name" is the string returned by `gda_entity_field_get_name()` on each of the fields composing `iface`. However, if that definition does not return any field, then each particular implementation of `iface` may try to give an extra definition to the notion of "field name".

For instance, in the case of the GdaQuery object, the `gda_entity_field_get_name()` is used as a first try to find a field, and if that fails, then the object tries to find fields from their SQL naming.

In the case where there can be more than one field with the same name (depending on `iface`'s implementation), then the returned value is `NULL`.

`iface` : | an object implementing the GdaEntity interface
`name` : |
Returns : | the requested GdaEntityField or `NULL` if the field cannot be found, or if more than one field has been found.

### gda_entity_get_field_by_xml_id ()

    GdaEntityField*     gda_entity_get_field_by_xml_id      (GdaEntity *iface,
                                                             const gchar *xml_id);

`iface` : | an object implementing the GdaEntity interface
`xml_id` : |
Returns : | the requested GdaEntityField

### gda_entity_get_field_by_index ()

    GdaEntityField*     gda_entity_get_field_by_index       (GdaEntity *iface,
                                                             gint index);

`iface` : | an object implementing the GdaEntity interface
`index` : |
Returns : | the requested GdaEntityField or NULL if the index is out of bounds

### gda_entity_get_field_index ()

    gint                gda_entity_get_field_index          (GdaEntity *iface,
                                                             GdaEntityField *field);

Get the position of the field in the given entity. Positions start at 0. `field` MUST be a visible field.

`iface` : | an object implementing the GdaEntity interface
`field` : | an object implementing the GdaEntityField interface
Returns : | the position or -1 if the field is not in the entity or is not visible

### gda_entity_add_field ()

    void                gda_entity_add_field                (GdaEntity *iface,
                                                             GdaEntityField *field);

Add `field` to `iface`'s fields (at the end of the list)

`iface` : | an object implementing the GdaEntity interface
`field` : | an object implementing the GdaEntityField interface to add

### gda_entity_add_field_before ()

    void                gda_entity_add_field_before         (GdaEntity *iface,
                                                             GdaEntityField *field,
                                                             GdaEntityField *field_before);

Add `field` to `iface`'s fields, before `field_before` if it is not `NULL`, or at the end if `field_before` is `NULL`.

`iface` : | an object implementing the GdaEntity interface
`field` : | an object implementing the GdaEntityField interface to add
`field_before` : | an object implementing the GdaEntityField interface before which `field` will be added, or `NULL`

### gda_entity_swap_fields ()

    void                gda_entity_swap_fields              (GdaEntity *iface,
                                                             GdaEntityField *field1,
                                                             GdaEntityField *field2);

`iface` : | an object implementing the GdaEntity interface
`field1` : | an object implementing the GdaEntityField interface
`field2` : | an object implementing the GdaEntityField interface

### gda_entity_remove_field ()

    void                gda_entity_remove_field             (GdaEntity *iface,
                                                             GdaEntityField *field);

`iface` : | an object implementing the GdaEntity interface
`field` : | an object implementing the GdaEntityField interface to remove

### gda_entity_is_writable ()

    gboolean            gda_entity_is_writable              (GdaEntity *iface);

Tells if the real entity (the corresponding DBMS object) represented by `iface` can be written to.

`iface` : | an object implementing the GdaEntity interface
Returns : | TRUE if it is possible to write to `iface`

## Signal Details

### The "field-added" signal

    void                user_function                      (GdaEntity      *gdaentity,
                                                            GdaEntityField *arg1,
                                                            gpointer        user_data)      : Run First

`dbentity` : | the object which received the signal.
`arg1` : |
`user_data` : | user data set when the signal handler was connected.

### The "field-removed" signal

    void                user_function                      (GdaEntity      *gdaentity,
                                                            GdaEntityField *arg1,
                                                            gpointer        user_data)      : Run First

`dbentity` : | the object which received the signal.
`arg1` : |
`user_data` : | user data set when the signal handler was connected.

### The "field-updated" signal

    void                user_function                      (GdaEntity      *gdaentity,
                                                            GdaEntityField *arg1,
                                                            gpointer        user_data)      : Run First

`dbentity` : | the object which received the signal.
`arg1` : |
`user_data` : | user data set when the signal handler was connected.

### The "fields-order-changed" signal

    void                user_function                      (GdaEntity *gdaentity,
                                                            gpointer   user_data)      : Run First

`dbentity` : | the object which received the signal.
`user_data` : | user data set when the signal handler was connected.