GdaMetaStruct: GNOME Data Access 5 manual

## GdaMetaStruct GdaMetaStruct — In memory representation of some database objects |

## Stability Level

Stable, unless otherwise indicated

## Functions

#define | GDA_META_DB_OBJECT()
#define | GDA_META_TABLE()
#define | GDA_META_VIEW()
#define | GDA_META_TABLE_COLUMN()
const GValue * | gda_meta_table_column_get_attribute ()
void | gda_meta_table_column_set_attribute ()
#define | gda_meta_table_column_set_attribute_static()
void | gda_meta_table_column_foreach_attribute ()
#define | GDA_META_TABLE_FOREIGN_KEY()
#define | GDA_META_TABLE_FOREIGN_KEY_ON_UPDATE_POLICY()
#define | GDA_META_TABLE_FOREIGN_KEY_ON_DELETE_POLICY()
#define | GDA_META_TABLE_FOREIGN_KEY_IS_DECLARED()
GdaMetaStruct * | gda_meta_struct_new ()
GdaMetaDbObject * | gda_meta_struct_complement ()
gboolean | gda_meta_struct_complement_schema ()
gboolean | gda_meta_struct_complement_default ()
gboolean | gda_meta_struct_complement_all ()
gboolean | gda_meta_struct_complement_depend ()
gboolean | gda_meta_struct_sort_db_objects ()
GSList * | gda_meta_struct_get_all_db_objects ()
GdaMetaDbObject * | gda_meta_struct_get_db_object ()
GdaMetaTableColumn * | gda_meta_struct_get_table_column ()
gchar * | gda_meta_struct_dump_as_graph ()

## Properties

guint | features | Read / Write / Construct Only
GdaMetaStore * | meta-store | Read / Write / Construct Only

## Types and Values

| GdaMetaStruct
enum | GdaMetaStructFeature
enum | GdaMetaStructError
enum | GdaMetaDbObjectType
| GdaMetaDbObject
| GdaMetaTable
| GdaMetaView
| GdaMetaTableColumn
enum | GdaMetaForeignKeyPolicy
| GdaMetaTableForeignKey
#define | GDA_META_STRUCT_ERROR
enum | GdaMetaSortType
enum | GdaMetaGraphInfo

## Object Hierarchy

        GObject
        ╰── GdaMetaStruct

## Includes

    #include <libgda/sql-parser/gda-sql-statement.h>

## Description

The GdaMetaStruct object reads data from a GdaMetaStore object and creates an easy to use in memory representation for some database objects. For example one can easily analyze the columns of a table (or its foreign keys) using a GdaMetaStruct.

When created, the new GdaMetaStruct object is empty (it does not have any information about any database object). Information about database objects is computed upon request using the `gda_meta_struct_complement()` method. Information about individual database objects is represented by GdaMetaDbObject structures, which can be obtained using `gda_meta_struct_get_db_object()` or `gda_meta_struct_get_all_db_objects()`.

Note that the GdaMetaDbObject structures may change or may be removed or replaced by others, so it not advised to keep pointers to these structures: pointers to these structures should be considered valid as long as `gda_meta_struct_complement()` and other similar functions have not been called.

In the following code sample, one prints the columns names and types of a table:

    GdaMetaStruct *mstruct;
    GdaMetaDbObject *dbo;
    GValue *catalog, *schema, *name;

    // Define name (and optionnally catalog and schema)
    [...]

    mstruct = gda_meta_struct_new ();
    gda_meta_struct_complement (mstruct, store, GDA_META_DB_TABLE, catalog, schema, name, NULL);
    dbo = gda_meta_struct_get_db_object (mstruct, catalog, schema, name);
    if (!dbo)
           g_print ("Table not found\n");
    else {
           GSList *list;
           for (list = GDA_META_TABLE (dbo)->columns; list; list = list->next) {
                   GdaMetaTableColumn *tcol = GDA_META_TABLE_COLUMN (list->data);
                   g_print ("COLUMN: %s (%s)\n", tcol->column_name, tcol->column_type);
           }
    }
    gda_meta_struct_free (mstruct);

If now the database object type is not known, one can use the following code:

    GdaMetaStruct *mstruct;
    GdaMetaDbObject *dbo;
    GValue *catalog, *schema, *name;

    // Define name (and optionnally catalog and schema)
    [...]

    mstruct = gda_meta_struct_new ();
    gda_meta_struct_complement (mstruct, store, GDA_META_DB_UNKNOWN, catalog, schema, name, NULL);
    dbo = gda_meta_struct_get_db_object (mstruct, catalog, schema, name);
    if (!dbo)
           g_print ("Object not found\n");
    else {
           if ((dbo->obj_type == GDA_META_DB_TABLE) || (dbo->obj_type == GDA_META_DB_VIEW)) {
                   if (dbo->obj_type == GDA_META_DB_TABLE)
                           g_print ("Is a table\n");
                   else if (dbo->obj_type == GDA_META_DB_VIEW) {
                           g_print ("Is a view, definition is:\n");
                           g_print ("%s\n", GDA_META_VIEW (dbo)->view_def);
                   }

                   GSList *list;
                   for (list = GDA_META_TABLE (dbo)->columns; list; list = list->next) {
                           GdaMetaTableColumn *tcol = GDA_META_TABLE_COLUMN (list->data);
                           g_print ("COLUMN: %s (%s)\n", tcol->column_name, tcol->column_type);
                   }
           }
           else
                   g_print ("Not a table or a view\n");
    }
    gda_meta_struct_free (mstruct);

## Functions

### GDA_META_DB_OBJECT()

    #define             GDA_META_DB_OBJECT(dbo)

Casts `dbo` to a GdaMetaDbObject, no check is made on the validity of `dbo`

#### Parameters

dbo | a pointer |

#### Returns

a pointer to a GdaMetaDbObject

### GDA_META_TABLE()

    #define             GDA_META_TABLE(dbobj)

Casts `dbo` to a GdaMetaTable, no check is made on the validity of `dbo`

#### Parameters

dbo | a pointer |

#### Returns

a pointer to a GdaMetaTable

### GDA_META_VIEW()

    #define             GDA_META_VIEW(dbobj)

Casts `dbo` to a GdaMetaView, no check is made on the validity of `dbo`

#### Parameters

dbo | a pointer |

#### Returns

a pointer to a GdaMetaView

### GDA_META_TABLE_COLUMN()

    #define             GDA_META_TABLE_COLUMN(col)

Casts `col` to a GdaMetaTableColumn, no check is made

#### Parameters

col | a pointer |

#### Returns

`col` , casted to a GdaMetaTableColumn

### gda_meta_table_column_get_attribute ()

    const GValue *
    gda_meta_table_column_get_attribute (GdaMetaTableColumn *tcol,
                                         const gchar *attribute);

Get the value associated to a named attribute.

Attributes can have any name, but Libgda proposes some default names, see this section.

#### Parameters

tcol | a GdaMetaTableColumn |
attribute | attribute name as a string |

#### Returns

a read-only GValue, or `NULL` if not attribute named `attribute` has been set for `column` .

[transfer none]

### gda_meta_table_column_set_attribute ()

    void
    gda_meta_table_column_set_attribute (GdaMetaTableColumn *tcol,
                                         const gchar *attribute,
                                         const GValue *value,
                                         GDestroyNotify destroy);

Set the value associated to a named attribute.

Attributes can have any name, but Libgda proposes some default names, see this section. If there is already an attribute named `attribute` set, then its value is replaced with the new `value` , except if `value` is `NULL`, in which case the attribute is removed.

Warning: `attribute` is not copied, if it needs to be freed when not used anymore, then `destroy` should point to the functions which will free it (typically `g_free()`). If `attribute` does not need to be freed, then `destroy` can be `NULL`.

#### Parameters

tcol | a GdaMetaTableColumn |
attribute | attribute name as a static string |
value | a GValue, or `NULL`. | [allow-none]
destroy | function called when `attribute` has to be freed, or `NULL`. | [allow-none]

### gda_meta_table_column_set_attribute_static()

    #define             gda_meta_table_column_set_attribute_static(column,attribute,value)

This function is similar to `gda_meta_table_column_set_attribute()` but for static strings

#### Parameters

column | a GdaMetaTableColumn |
attribute | attribute's name |
value | a GValue, or `NULL`. | [allow-none]

### gda_meta_table_column_foreach_attribute ()

    void
    gda_meta_table_column_foreach_attribute
                                   (GdaMetaTableColumn *tcol,
                                    GdaAttributesManagerFunc func,
                                    gpointer data);

Calls `func` for each attribute set to tcol

#### Parameters

tcol | a GdaMetaTableColumn |
func | a GdaAttributesManagerFunc function. | [scope call]
data | user data to be passed as last argument of `func` each time it is called. | [closure]

### GDA_META_TABLE_FOREIGN_KEY()

    #define             GDA_META_TABLE_FOREIGN_KEY(fk)

Casts `fk` to a GdaMetaTableForeignKey (no check is actuelly being done on `fk` 's validity)

#### Parameters

fk | a pointer |

#### Returns

`col` , casted to a GdaMetaTableForeignKey

### GDA_META_TABLE_FOREIGN_KEY_ON_UPDATE_POLICY()

    #define             GDA_META_TABLE_FOREIGN_KEY_ON_UPDATE_POLICY(fk)

Tells the actual policy implemented by `fk` when used in the context of an UPDATE.

#### Parameters

fk | a pointer to a GdaMetaTableForeignKey |

#### Returns

the policy as a GdaMetaForeignKeyPolicy

### GDA_META_TABLE_FOREIGN_KEY_ON_DELETE_POLICY()

    #define             GDA_META_TABLE_FOREIGN_KEY_ON_DELETE_POLICY(fk)

Tells the actual policy implemented by `fk` when used in the context of a DELETE.

#### Parameters

fk | a pointer to a GdaMetaTableForeignKey |

#### Returns

the policy as a GdaMetaForeignKeyPolicy

### GDA_META_TABLE_FOREIGN_KEY_IS_DECLARED()

    #define             GDA_META_TABLE_FOREIGN_KEY_IS_DECLARED(fk)

Tells if `fk` is an actual foreign key defined in the database's schema, or if it is an indication which has been added to help Libgda understand the database schema.

#### Parameters

fk | a pointer to a GdaMetaTableForeignKey |

#### Returns

`TRUE` if `fk` has been declared in the database's meta data and `FALSE` if `fk` is an actual foreign key defined in the database's schema

### gda_meta_struct_new ()

    GdaMetaStruct *
    gda_meta_struct_new (GdaMetaStore *store,
                         GdaMetaStructFeature features);

Creates a new GdaMetaStruct object. The `features` specifies the extra features which will also be computed: the more features, the more time it takes to run. Features such as table's columns, each column's attributes, etc are not optional and will always be computed.

#### Parameters

store | a GdaMetaStore from which the new GdaMetaStruct object will fetch information |
features | the kind of extra information the new GdaMetaStruct object will compute |

#### Returns

the newly created GdaMetaStruct object.

[transfer full]

### gda_meta_struct_complement ()

    GdaMetaDbObject *
    gda_meta_struct_complement (GdaMetaStruct *mstruct,
                                GdaMetaDbObjectType type,
                                const GValue *catalog,
                                const GValue *schema,
                                const GValue *name,
                                GError **error);

Creates a new GdaMetaDbObject structure in `mstruct` to represent the database object (of type `type` ) which can be uniquely identified as `catalog` .`schema` .`name` .

If `catalog` is not `NULL`, then `schema` should not be `NULL`.

If both `catalog` and `schema` are `NULL`, then the database object will be the one which is "visible" by default (that is which can be accessed only by its short `name` name).

If `catalog` is `NULL` and `schema` is not `NULL`, then the database object will be the one which can be accessed by its `schema` .`name` name.

Important note: `catalog` , `schema` and `name` will be used using the following convention:

- be surrounded by double quotes for a case sensitive search

- otherwise for case insensitive search

For more information, see the meta data section about SQL identifiers.

#### Parameters

mstruct | a GdaMetaStruct object |
type | the type of object to add (which can be GDA_META_DB_UNKNOWN) |
catalog | the catalog the object belongs to (as a G_TYPE_STRING GValue), or `NULL`. | [allow-none]
schema | the schema the object belongs to (as a G_TYPE_STRING GValue), or `NULL`. | [allow-none]
name | the object's name (as a G_TYPE_STRING GValue), not `NULL` |
error | a place to store errors, or `NULL`. | [allow-none]

#### Returns

the GdaMetaDbObject corresponding to the database object if no error occurred, or `NULL`.

[transfer none]

### gda_meta_struct_complement_schema ()

    gboolean
    gda_meta_struct_complement_schema (GdaMetaStruct *mstruct,
                                       const GValue *catalog,
                                       const GValue *schema,
                                       GError **error);

This method is similar to `gda_meta_struct_complement()` but creates GdaMetaDbObject for all the database object which are in the `schema` schema (and in the `catalog` catalog). If `catalog` is `NULL`, then any catalog will be used, and if `schema` is `NULL` then any schema will be used (if `schema` is `NULL` then catalog must also be `NULL`).

Please refer to `gda_meta_struct_complement()` form more information.

#### Parameters

mstruct | a GdaMetaStruct object |
catalog | name of a catalog, or `NULL`. | [allow-none]
schema | name of a schema, or `NULL`. | [allow-none]
error | a place to store errors, or `NULL`. | [allow-none]

#### Returns

TRUE if no error occurred

### gda_meta_struct_complement_default ()

    gboolean
    gda_meta_struct_complement_default (GdaMetaStruct *mstruct,
                                        GError **error);

This method is similar to `gda_meta_struct_complement()` and `gda_meta_struct_complement_all()` but creates GdaMetaDbObject for all the database object which are usable using only their short name (that is which do not need to be prefixed by the schema in which they are to be used).

Please refer to `gda_meta_struct_complement()` form more information.

#### Parameters

mstruct | a GdaMetaStruct object |
error | a place to store errors, or `NULL`. | [allow-none]

#### Returns

TRUE if no error occurred

### gda_meta_struct_complement_all ()

    gboolean
    gda_meta_struct_complement_all (GdaMetaStruct *mstruct,
                                    GError **error);

This method is similar to `gda_meta_struct_complement()` and `gda_meta_struct_complement_default()` but creates GdaMetaDbObject for all the database object.

Please refer to `gda_meta_struct_complement()` form more information.

#### Parameters

mstruct | a GdaMetaStruct object |
error | a place to store errors, or `NULL`. | [allow-none]

#### Returns

TRUE if no error occurred

### gda_meta_struct_complement_depend ()

    gboolean
    gda_meta_struct_complement_depend (GdaMetaStruct *mstruct,
                                       GdaMetaDbObject *dbo,
                                       GError **error);

This method is similar to `gda_meta_struct_complement()` but creates GdaMetaDbObject for all the dependencies of `dbo` .

Please refer to `gda_meta_struct_complement()` form more information.

#### Parameters

mstruct | a GdaMetaStruct object |
dbo | a GdaMetaDbObject part of `mstruct` |
error | a place to store errors, or `NULL`. | [allow-none]

#### Returns

TRUE if no error occurred

### gda_meta_struct_sort_db_objects ()

    gboolean
    gda_meta_struct_sort_db_objects (GdaMetaStruct *mstruct,
                                     GdaMetaSortType sort_type,
                                     GError **error);

Reorders the list of database objects within `mstruct` in a way specified by `sort_type` .

#### Parameters

mstruct | a GdaMetaStruct object |
sort_type | the kind of sorting requested |
error | a place to store errors, or `NULL`. | [allow-none]

#### Returns

TRUE if no error occurred

### gda_meta_struct_get_all_db_objects ()

    GSList *
    gda_meta_struct_get_all_db_objects (GdaMetaStruct *mstruct);

Get a list of all the GdaMetaDbObject structures representing database objects in `mstruct` . Note that no GdaMetaDbObject structure must not be modified.

#### Parameters

mstruct | a GdaMetaStruct object |

#### Returns

a new GSList list of pointers to GdaMetaDbObject structures which must be destroyed after usage using `g_slist_free()`. The individual GdaMetaDbObject must not be modified.

[transfer container][element-type Gda.MetaDbObject]

### gda_meta_struct_get_db_object ()

    GdaMetaDbObject *
    gda_meta_struct_get_db_object (GdaMetaStruct *mstruct,
                                   const GValue *catalog,
                                   const GValue *schema,
                                   const GValue *name);

Tries to locate the GdaMetaDbObject structure representing the database object named after `catalog` , `schema` and `name` .

If one or both of `catalog` and `schema` are `NULL`, and more than one database object matches the name, then the return value is also `NULL`.

#### Parameters

mstruct | a GdaMetaStruct object |
catalog | the catalog the object belongs to (as a G_TYPE_STRING GValue), or `NULL`. | [allow-none]
schema | the schema the object belongs to (as a G_TYPE_STRING GValue), or `NULL`. | [allow-none]
name | the object's name (as a G_TYPE_STRING GValue), not `NULL` |

#### Returns

the GdaMetaDbObject or `NULL` if not found.

[transfer none]

### gda_meta_struct_get_table_column ()

    GdaMetaTableColumn *
    gda_meta_struct_get_table_column (GdaMetaStruct *mstruct,
                                      GdaMetaTable *table,
                                      const GValue *col_name);

Tries to find the GdaMetaTableColumn representing the column named `col_name` in `table` .

[skip]

#### Parameters

mstruct | a GdaMetaStruct object |
table | the GdaMetaTable structure to find the column for |
col_name | the name of the column to find (as a G_TYPE_STRING GValue) |

#### Returns

the GdaMetaTableColumn or `NULL` if not found.

[transfer none]

### gda_meta_struct_dump_as_graph ()

    gchar *
    gda_meta_struct_dump_as_graph (GdaMetaStruct *mstruct,
                                   GdaMetaGraphInfo info,
                                   GError **error);

Creates a new graph (in the GraphViz syntax) representation of `mstruct` .

#### Parameters

mstruct | a GdaMetaStruct object |
info | informs what kind of information to show in the resulting graph |
error | a place to store errors, or `NULL`. | [allow-none]

#### Returns

a new string, or `NULL` if an error occurred.

[transfer full]

## Types and Values

### GdaMetaStruct

    typedef struct _GdaMetaStruct GdaMetaStruct;

### enum GdaMetaStructFeature

Controls which features are computed about database objects.

#### Members

GDA_META_STRUCT_FEATURE_NONE | database objects only have their own attributes |
GDA_META_STRUCT_FEATURE_FOREIGN_KEYS | foreign keys are computed for tables |
GDA_META_STRUCT_FEATURE_VIEW_DEPENDENCIES | for views, the tables they use are also computed |
GDA_META_STRUCT_FEATURE_ALL | all the features are computed |

### enum GdaMetaStructError

#### Members

GDA_META_STRUCT_UNKNOWN_OBJECT_ERROR |  |
GDA_META_STRUCT_DUPLICATE_OBJECT_ERROR |  |
GDA_META_STRUCT_INCOHERENCE_ERROR |  |
GDA_META_STRUCT_XML_ERROR |  |

### enum GdaMetaDbObjectType

Type of database object which can be handled as a GdaMetaDbObject

#### Members

GDA_META_DB_UNKNOWN | unknown type |
GDA_META_DB_TABLE | represents a table |
GDA_META_DB_VIEW | represents a view |

### GdaMetaDbObject

    typedef struct {
    	union {
    		GdaMetaTable    meta_table;
    		GdaMetaView     meta_view;
    	}                       extra;
    	GdaMetaDbObjectType     obj_type;
    	gboolean                outdated;
    	gchar                  *obj_catalog;
    	gchar                  *obj_schema;
    	gchar                  *obj_name;
    	gchar                  *obj_short_name;
    	gchar                  *obj_full_name;
    	gchar                  *obj_owner;

    	GSList                 *depend_list;
    } GdaMetaDbObject;

Struture to hold information about each database object (tables, views, ...), its contents must not be modified.

Note: `obj_catalog` , `obj_schema` , `obj_name` , `obj_short_name` and `obj_full_name` respect the

SQL identifiers convention used in

GdaMetaStore objects. Before using these SQL identifiers, you should check the `gda_sql_identifier_quote()` to know if is it is necessary to surround by double quotes before using in an SQL statement.

#### Members

GdaMetaDbObjectType `obj_type`; | the type of object (table, view) |
gboolean `outdated`; | set to `TRUE` if the information in this GdaMetaDbObject may be outdated because the GdaMetaStore has been updated |
gchar *`obj_catalog`; | the catalog the object is in |
gchar *`obj_schema`; | the schema the object is in |
gchar *`obj_name`; | the object's name |
gchar *`obj_short_name`; | the shortest way to name the object |
gchar *`obj_full_name`; | the full name of the object (in the <schema>.<nameagt; notation |
gchar *`obj_owner`; | object's owner |
GSList *`depend_list`; | list of GdaMetaDbObject pointers on which this object depends (through foreign keys or tables used for views). | [element-type Gda.MetaDbObject]

### GdaMetaTable

    typedef struct {
    	GSList       *columns;

    	/* PK fields index */
    	gint         *pk_cols_array;
    	gint          pk_cols_nb;

    	/* Foreign keys */
    	GSList       *reverse_fk_list; /* list of GdaMetaTableForeignKey where @depend_on == this GdaMetaDbObject */
    	GSList       *fk_list; /* list of GdaMetaTableForeignKey where @meta_table == this GdaMetaDbObject */
    } GdaMetaTable;

This structure specifies a GdaMetaDbObject to represent a table's specific attributes, its contents must not be modified.

Note that in some cases, the columns cannot be determined for views, and in this case the `columns` will be `NULL` (this can be the case for example with SQLite where a view uses a function which is not natively provided by SQLite.

#### Members

GSList *`columns`; | list of GdaMetaTableColumn structures, one for each column in the table. | [element-type Gda.MetaTableColumn]
gint *`pk_cols_array`; | index of the columns part of the primary key for the table (WARNING: columns numbering here start at 0) |
gint `pk_cols_nb`; | size of the `pk_cols_array` array |
GSList *`reverse_fk_list`; | list of GdaMetaTableForeignKey where the referenced table is this table. | [element-type Gda.MetaTableForeignKey]
GSList *`fk_list`; | list of GdaMetaTableForeignKey for this table. | [element-type Gda.MetaTableForeignKey]

### GdaMetaView

    typedef struct {
    	GdaMetaTable  table;
    	gchar        *view_def;
    	gboolean      is_updatable;
    } GdaMetaView;

This structure specifies a GdaMetaDbObject to represent a view's specific attributes, its contents must not be modified.

#### Members

GdaMetaTable `table`; | a view is also a table as it has columns |
gchar *`view_def`; | views' definition |
gboolean `is_updatable`; | tells if the view's contents can be updated |

### GdaMetaTableColumn

    typedef struct {
    	gchar        *column_name;
    	gchar        *column_type;
    	GType         gtype;
    	gboolean      pkey;
    	gboolean      nullok;
    	gchar        *default_value;
    } GdaMetaTableColumn;

This structure represents a table of view's column, its contents must not be modified.

#### Members

gchar *`column_name`; | the column's name |
gchar *`column_type`; | the column's DBMS's type |
GType `gtype`; | the detected column's GType |
gboolean `pkey`; | tells if the column is part of a primary key |
gboolean `nullok`; | tells if the column can be `NULL` |
gchar *`default_value`; | the column's default value, represented as a valid SQL value (surrounded by simple quotes for strings, ...), or `NULL` if column has no default value. | [allow-none]

### enum GdaMetaForeignKeyPolicy

Defines the filtering policy of a foreign key when invoked on an UPDATE or DELETE operation.

#### Members

GDA_META_FOREIGN_KEY_UNKNOWN | unspecified policy |
GDA_META_FOREIGN_KEY_NONE | not enforced policy |
GDA_META_FOREIGN_KEY_NO_ACTION | return an error, no action taken |
GDA_META_FOREIGN_KEY_RESTRICT | same as `GDA_META_FOREIGN_KEY_NO_ACTION` , not deferrable |
GDA_META_FOREIGN_KEY_CASCADE | policy is to delete any rows referencing the deleted row, or update the value of the referencing column to the new value of the referenced column, respectively |
GDA_META_FOREIGN_KEY_SET_NULL | policy is to set the referencing column to NULL |
GDA_META_FOREIGN_KEY_SET_DEFAULT | policy is to set the referencing column to its default value |

### GdaMetaTableForeignKey

    typedef struct {
    	GdaMetaDbObject  *meta_table;
    	GdaMetaDbObject  *depend_on;

    	gint              cols_nb;
    	gint             *fk_cols_array; /* FK fields index */
    	gchar           **fk_names_array; /* FK fields names */
    	gint             *ref_pk_cols_array; /* Ref PK fields index */
    	gchar           **ref_pk_names_array; /* Ref PK fields names */

    	gchar            *fk_name;
    } GdaMetaTableForeignKey;

This structure represents a foreign key constraint, its contents must not be modified.

#### Members

GdaMetaDbObject *`meta_table`; | the GdaMetaDbObject for which this structure represents a foreign key |
GdaMetaDbObject *`depend_on`; | the GdaMetaDbObject which is referenced by the foreign key |
gint `cols_nb`; | the size of the `fk_cols_array` , `fk_names_array` , `ref_pk_cols_array` and `ref_pk_names_array` arrays |
gint *`fk_cols_array`; | the columns' indexes in `meta_table` which participate in the constraint (WARNING: columns numbering here start at 1) |
gchar **`fk_names_array`; | the columns' names in `meta_table` which participate in the constraint |
gint *`ref_pk_cols_array`; | the columns' indexes in `depend_on` which participate in the constraint (WARNING: columns numbering here start at 1) |
gchar **`ref_pk_names_array`; | the columns' names in `depend_on` which participate in the constraint |
gchar *`fk_name`; |  |

### GDA_META_STRUCT_ERROR

    #define             GDA_META_STRUCT_ERROR

### enum GdaMetaSortType

Types of sorting

#### Members

GDA_META_SORT_ALHAPETICAL | sort alphabetically |
GDA_META_SORT_DEPENDENCIES | sort by dependencies |

### enum GdaMetaGraphInfo

#### Members

GDA_META_GRAPH_COLUMNS |  |

## Property Details

### The `“features”` property

      “features”                 guint

Flags: Read / Write / Construct Only

Allowed values: <= G_MAXINT

Default value: 3

### The `“meta-store”` property

      “meta-store”               GdaMetaStore *

GdaMetaStore object to fetch information from.

Flags: Read / Write / Construct Only

## See Also

GdaMetaStore