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GNOME Data Access 4.0 manual | ![]() |
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GdaMetaStruct; enum GdaMetaStructFeature; enum GdaMetaStructError; enum GdaMetaDbObjectType; GdaMetaDbObject; #define GDA_META_DB_OBJECT (x) #define GDA_META_TABLE (dbobj) #define GDA_META_VIEW (dbobj) GdaMetaTable; GdaMetaView; GdaMetaTableColumn; #define GDA_META_TABLE_COLUMN (x) const GValue* gda_meta_table_column_get_attribute (GdaMetaTableColumn *tcol, const gchar *att_name); void gda_meta_table_column_set_attribute (GdaMetaTableColumn *tcol, const gchar *att_name, const GValue *value, GDestroyNotify destroy); #define gda_meta_table_column_set_attribute_static(holder,attribute,value) void gda_meta_table_column_foreach_attribute (GdaMetaTableColumn *tcol, GdaAttributesManagerFunc func, gpointer data); GdaMetaTableForeignKey; #define GDA_META_TABLE_FOREIGN_KEY (x) #define GDA_META_STRUCT_ERROR GdaMetaStruct* gda_meta_struct_new (GdaMetaStore *store, GdaMetaStructFeature features); GdaMetaDbObject* gda_meta_struct_complement (GdaMetaStruct *mstruct, GdaMetaDbObjectType type, const GValue *catalog, const GValue *schema, const GValue *name, GError **error); gboolean gda_meta_struct_complement_schema (GdaMetaStruct *mstruct, const GValue *catalog, const GValue *schema, GError **error); gboolean gda_meta_struct_complement_default (GdaMetaStruct *mstruct, GError **error); gboolean gda_meta_struct_complement_all (GdaMetaStruct *mstruct, GError **error); gboolean gda_meta_struct_complement_depend (GdaMetaStruct *mstruct, GdaMetaDbObject *dbo, GError **error); enum GdaMetaSortType; gboolean gda_meta_struct_sort_db_objects (GdaMetaStruct *mstruct, GdaMetaSortType sort_type, GError **error); GSList* gda_meta_struct_get_all_db_objects (GdaMetaStruct *mstruct); GdaMetaDbObject* gda_meta_struct_get_db_object (GdaMetaStruct *mstruct, const GValue *catalog, const GValue *schema, const GValue *name); GdaMetaTableColumn* gda_meta_struct_get_table_column (GdaMetaStruct *mstruct, GdaMetaTable *table, const GValue *col_name); enum GdaMetaGraphInfo; gchar* gda_meta_struct_dump_as_graph (GdaMetaStruct *mstruct, GdaMetaGraphInfo info, GError **error);
"features" guint : Read / Write / Construct Only "meta-store" GdaMetaStore* : Read / Write / Construct Only
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 analyse 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);
typedef enum { GDA_META_STRUCT_FEATURE_NONE = 0, GDA_META_STRUCT_FEATURE_FOREIGN_KEYS = 1 << 0, GDA_META_STRUCT_FEATURE_VIEW_DEPENDENCIES = 1 << 1, GDA_META_STRUCT_FEATURE_ALL = GDA_META_STRUCT_FEATURE_FOREIGN_KEYS | GDA_META_STRUCT_FEATURE_VIEW_DEPENDENCIES } GdaMetaStructFeature;
typedef enum { GDA_META_STRUCT_UNKNOWN_OBJECT_ERROR, GDA_META_STRUCT_DUPLICATE_OBJECT_ERROR, GDA_META_STRUCT_INCOHERENCE_ERROR } GdaMetaStructError;
typedef enum { GDA_META_DB_UNKNOWN, GDA_META_DB_TABLE, GDA_META_DB_VIEW } GdaMetaDbObjectType;
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; /* list of GdaMetaDbObject pointers on which this object depends */ } GdaMetaDbObject;
Struture to hold information about each database object (tables, views, triggers, ...)
Note: obj_catalog
, obj_schema
, obj_name
, obj_short_name
and obj_full_name
are case sensitive:
one must call gda_sql_identifier_needs_quotes()
to know if is it is necessary to surround by double quotes
before using in an SQL statement
typedef struct { GSList *columns; /* list of GdaMetaTableColumn */ /* 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;
typedef struct { GdaMetaTable table; gchar *view_def; gboolean is_updatable; } GdaMetaView;
typedef struct { gchar *column_name; gchar *column_type; GType gtype; gboolean pkey; gboolean nullok; gchar *default_value; } GdaMetaTableColumn;
const GValue* gda_meta_table_column_get_attribute (GdaMetaTableColumn *tcol, const gchar *att_name);
Get the value associated to a named attribute.
Attributes can have any name, but Libgda proposes some default names, see this section.
|
a GdaMetaTableColumn |
|
|
Returns : |
a read-only GValue, or NULL if not attribute named attribute has been set for column
|
void gda_meta_table_column_set_attribute (GdaMetaTableColumn *tcol, const gchar *att_name, 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
.
|
a GdaMetaTableColumn |
|
|
|
a GValue, or NULL
|
|
function called when attribute has to be freed, or NULL
|
#define gda_meta_table_column_set_attribute_static(holder,attribute,value) gda_meta_table_column_set_attribute((holder),(attribute),(value),NULL)
This function is similar to gda_meta_table_column_set_attribute()
but for static strings
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void gda_meta_table_column_foreach_attribute (GdaMetaTableColumn *tcol, GdaAttributesManagerFunc func, gpointer data);
Calls func
for each attribute set to tcol
|
a GdaMetaTableColumn |
|
a GdaAttributesManagerFunc function |
|
user data to be passed as last argument of func each time it is called
|
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 */ } GdaMetaTableForeignKey;
#define GDA_META_TABLE_FOREIGN_KEY(x) ((GdaMetaTableForeignKey*)(x))
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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.
|
a GdaMetaStore from which the new GdaMetaStruct object will fetch information |
|
the kind of extra information the new GdaMetaStruct object will compute |
Returns : |
the newly created GdaMetaStruct object |
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
must respect the following convention:
be surrounded by double quotes for a case sensitive search
otherwise they will be converted to lower case for search
|
a GdaMetaStruct object |
|
the type of object to add (which can be GDA_META_DB_UNKNOWN) |
|
the catalog the object belongs to (as a G_TYPE_STRING GValue), or NULL
|
|
the schema the object belongs to (as a G_TYPE_STRING GValue), or NULL
|
|
the object's name (as a G_TYPE_STRING GValue), not NULL
|
|
a place to store errors, or NULL
|
Returns : |
the GdaMetaDbObject corresponding to the database object if no error occurred, or NULL
|
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
).
|
a GdaMetaStruct object |
|
name of a catalog, or NULL
|
|
name of a schema, or NULL
|
|
a place to store errors, or NULL
|
Returns : |
TRUE if no error occurred |
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 useable using only their short name (that is which do not need to be prefixed by
the schema in which they are to be used).
|
a GdaMetaStruct object |
|
a place to store errors, or NULL
|
Returns : |
TRUE if no error occurred |
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.
|
a GdaMetaStruct object |
|
a place to store errors, or NULL
|
Returns : |
TRUE if no error occurred |
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
.
|
a GdaMetaStruct object |
|
a GdaMetaDbObject part of mstruct
|
|
a place to store errors, or NULL
|
Returns : |
TRUE if no error occurred |
typedef enum { GDA_META_SORT_ALHAPETICAL, GDA_META_SORT_DEPENDENCIES } GdaMetaSortType;
sort by alphabetical order on the schema name and on the object name | |
sort such as that for any given GdaMetaDbObject in the list, all its dependencies are _before_ it in the list |
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
.
|
a GdaMetaStruct object |
|
the kind of sorting requested |
|
a place to store errors, or NULL
|
Returns : |
TRUE if no error occurred |
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.
|
a GdaMetaStruct object |
Returns : |
a new GSList list of pointers which must be destroyed after usage using g_slist_free() .
|
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
.
|
a GdaMetaStruct object |
|
the catalog the object belongs to (as a G_TYPE_STRING GValue), or NULL
|
|
the schema the object belongs to (as a G_TYPE_STRING GValue), or NULL
|
|
the object's name (as a G_TYPE_STRING GValue), not NULL
|
Returns : |
the GdaMetaDbObject or NULL if not found
|
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
.
|
a GdaMetaStruct object |
|
the GdaMetaTable structure to find the column for |
|
the name of the column to find (as a G_TYPE_STRING GValue) |
Returns : |
the GdaMetaTableColumn or NULL if not found
|
gchar* gda_meta_struct_dump_as_graph (GdaMetaStruct *mstruct, GdaMetaGraphInfo info, GError **error);
Creates a new graph (in the GraphViz syntax) representation of mstruct
.
|
a GdaMetaStruct object |
|
informs what kind of information to show in the resulting graph |
|
a place to store errors, or NULL
|
Returns : |
a new string, or NULL if an error occurred.
|
"features"
property"features" guint : Read / Write / Construct Only
Allowed values: <= G_MAXINT
Default value: 3
"meta-store"
property"meta-store" GdaMetaStore* : Read / Write / Construct Only
GdaMetaStore object to fetch information from.