OrientDB-NET - DatabaseExists()

This method determines whether or not a database exists already on the OrientDB Server. It returns a boolean value indicating what it finds.

Checking Databases

In order to check that databases exist on the server, you first need to create an OServer instance. Once you have it, you can call the DatabaseExists() method on it.

Syntax

bool OServer.DatabaseExists(
   string <name>,
   OStorageType <storage>)

• <name> Defines the name of the database you want.
• <storage> Defines the storage type you want, such as PLocal or Memory.

The method returns a boolean value, indicating whether or not it found the requested database on the server.

Example

For instance, say that you have a complex application that utilizes several databases in-memory on an OrientDB Server. The in-memory storage type is volatile and is lost in the event that the server shuts down or the host crashes. As such, you may want to create a basic test function to determine whether a series of databases exist on the server before you attempt operations. If the database doesn't exist, you'll need to create it.

using Orient.Client;
using System;
...

// CHECK THAT DATABASES EXIST
public void checkDatabases(OServer server, string[] databases)
{
   Console.WriteLine("Checking that databases exists...");

   // LOOP OVER EACH REQUIRED DATABASE
   foreach(string database in databases)
   {
      // DETERMINE IF DATABASE EXISTS
      bool dbExists = server.DatabaseExists(database,
         OStorageType.Memory);

      // CREATE DATABASE 
      if(dbExists == false)
      {
         Console.WriteLine("Database {0} doesn't exist, creating...",
            database);
         // CREATE NONEXISTENT DATABASE
         server.CreateDatabase(database,
            ODatabaseType.Graph,
            OStorageType.Memory);
      }

      // REPORT IF DATABASE EXISTS
      else
      {
          Console.WriteLine("Database {0} exists already",
             database);
      }
   }   
}