Administration and configuration
Administrative commands
Administrative commands should not be used during a rolling upgrade. For more information, see Upgrade and Migration Guide → Upgrade a cluster. For detailed information on Cypher administrative commands, see Cypher Manual → Database management. |
Before using administrative commands, it is important to understand the difference between stopped databases, and dropped databases:
-
Databases that are stopped with the
STOP
command are completely shutdown, and may be started again through theSTART
command. In a cluster, as long as a database is in a shutdown state, it can not be considered available to other members of the cluster. It is not possible to do online backups against shutdown databases and they need to be taken into special consideration during disaster recovery, as they do not have a running Raft machine while shutdown. -
Dropped databases are completely removed and are not intended to be used again at all.
The following Cypher commands are used on the system
database to manage multiple databases:
Command | Description |
---|---|
|
Create and start a new database. Enterprise Edition |
|
Drop (remove) an existing database. Enterprise Edition |
|
Alter (modify) an existing database. Enterprise Edition |
|
Start a database that has been stopped. |
|
Shut down a database. |
|
Show the status of a specific database. |
|
Show the name and status of all the databases. |
|
Show the name and status of the default database. |
|
Show the name and status of the home database for the current user. |
Naming rules for databases are as follows:
-
Length must be between 3 and 63 characters.
-
The first character of a name must be an ASCII alphabetic character.
-
Subsequent characters must be ASCII alphabetic or numeric characters, dots or dashes;
[a..z][0..9].-
-
Names are case-insensitive and normalized to lowercase.
-
Names that begin with an underscore and with the prefix
system
are reserved for internal use.
All of the above commands are executed as Cypher commands, and the database name is subject to the standard Cypher restrictions on valid identifiers.
In particular, the |
It is possible to create an alias to refer to an existing database to avoid these restrictions. For more information, see Cypher Manual → Creating database aliases.
For detailed information on Cypher administrative commands, see Cypher Manual → Access Control.
For examples of using the Cypher administrative commands to manage multiple active databases, see Queries.
Configuration parameters
Configuration parameters are defined in the neo4j.conf file.
The following configuration parameters are applicable for managing databases:
Parameter name | Description | ||||
---|---|---|---|---|---|
Name of the default database for the Neo4j instance. The database is created if it does not exist when the instance starts. Default value:
|
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Maximum number of databases that can be used in a Neo4j single instance or cluster. The number includes all the online and offline databases. The value is an integer with a minimum value of 2. Enterprise Edition Default value:
|
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Default mode of all databases.
If this setting is set to Default value: |
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List of database names for which to prevent write queries.
This set can contain also not yet existing databases, but not the
Example configuration:
|
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List of database names for which to accept write queries.
This set can contain also not yet existing databases.
Example configuration:
|
Although it is possible to achieve the same goal, i.e. set a database to read-only, both by using the Cypher command Using configuration parameters is more subtle and allows you to configure access on each instance separately, in case of a cluster for example.
If you use If both the Cypher command and the configuration parameters are used and they contain conflicting information, the database in question is set to read-only. |
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