Querying Metadata
OrientDB provides the metadata: target to retrieve information about OrientDB's metadata:
schema, to get classes and propertiesindexmanager, to get information about indexesdatabase, to get information about the databasestorage, to get information about the storage
Querying the Schema
Get all the configured classes:
select expand(classes) from metadata:schema
----+-----------+---------+----------------+----------+--------+--------+----------+----------+------------+----------
# |name |shortName|defaultClusterId|strictMode|abstract|overSize|clusterIds|properties|customFields|superClass
----+-----------+---------+----------------+----------+--------+--------+----------+----------+------------+----------
0 |UserGroup |null |13 |false |false |0.0 |[1] |[2] |null |V
1 |WallPost |null |15 |false |false |0.0 |[1] |[4] |null |V
2 |Owner |null |12 |false |false |0.0 |[1] |[1] |null |E
3 |OTriggered |null |-1 |false |true |0.0 |[1] |[0] |null |null
4 |E |E |10 |false |false |0.0 |[1] |[0] |null |null
5 |OUser |null |5 |false |false |0.0 |[1] |[4] |null |OIdentity
6 |OSchedule |null |7 |false |false |0.0 |[1] |[7] |null |null
7 |ORestricted|null |-1 |false |true |0.0 |[1] |[4] |null |null
8 |AssignedTo |null |11 |false |false |0.0 |[1] |[1] |null |E
9 |V |null |9 |false |false |2.0 |[1] |[0] |null |null
10 |OFunction |null |6 |false |false |0.0 |[1] |[5] |null |null
11 |ORole |null |4 |false |false |0.0 |[1] |[4] |null |OIdentity
12 |ORIDs |null |8 |false |false |0.0 |[1] |[0] |null |null
13 |OIdentity |null |-1 |false |true |0.0 |[1] |[0] |null |null
14 |User |null |14 |false |false |0.0 |[1] |[2] |null |V
----+-----------+---------+----------------+----------+--------+--------+----------+----------+------------+----------
Get all the configured properties for the class OUser:
select expand(properties) from (
select expand(classes) from metadata:schema
) where name = 'OUser'
----+--------+----+---------+--------+-------+----+----+------+------------+-----------
# |name |type|mandatory|readonly|notNull|min |max |regexp|customFields|linkedClass
----+--------+----+---------+--------+-------+----+----+------+------------+-----------
0 |status |7 |true |false |true |null|null|null |null |null
1 |roles |15 |false |false |false |null|null|null |null |ORole
2 |password|7 |true |false |true |null|null|null |null |null
3 |name |7 |true |false |true |null|null|null |null |null
----+--------+----+---------+--------+-------+----+----+------+------------+-----------
Get only the configured customFields properties for OUser (assuming you added CUSTOM metadata like foo=bar):
select customFields from (
select expand(classes) from metadata:schema
) where name="OUser"
----+------+------------
# |@CLASS|customFields
----+------+------------
0 |null |{foo=bar}
----+------+------------
Or, if you wish to get only the configured customFields of an attribute, like if you had a comment for the password attribute for the OUser class.
select customFields from (
select expand(properties) from (
select expand(classes) from metadata:schema
) where name="OUser"
) where name="password"
----+------+----------------------------------------------------
# |@CLASS|customFields
----+------+----------------------------------------------------
0 |null |{comment=Foo Bar your password to keep it secure!}
----+------+----------------------------------------------------
Querying the available Indexes
Get all the configured indexes:
select expand(indexes) from metadata:indexmanager
----+------+------+--------+---------+---------+------------------------------------+------------------------------------------------------
# |@RID |mapRid|clusters|type |name |indexDefinition |indexDefinitionClass
----+------+------+--------+---------+---------+------------------------------------+------------------------------------------------------
0 |#-1:-1|#2:0 |[0] |DICTIO...|dictio...|{keyTypes:[1]} |com.orientechnologies.orient.core.index.OSimpleKeyI...
1 |#-1:-1|#1:1 |[1] |UNIQUE |OUser....|{className:OUser,field:name,keyTy...|com.orientechnologies.orient.core.index.OPropertyIn...
2 |#-1:-1|#1:0 |[1] |UNIQUE |ORole....|{className:ORole,field:name,keyTy...|com.orientechnologies.orient.core.index.OPropertyIn...
----+------+------+--------+---------+---------+------------------------------------+-----------------------------------------
Querying database and storage metadata
Querying database metadata:
SELECT FROM metadata:database
Querying storage metadata:
SELECT FROM metadata:storage