Database Functions

In previous exmaples, such as factorial(), the function is relatively self-contained. It takes an argument from the query, operates on it, and returns the result. This is useful in cases where you need to perform some routine arithmetic operation or manipulate strings in a consistent way, but you can also use functions to perform more complex database operations. That is, the function can receive arguments, interact with the database, then return the results of that interaction.

Database Variable

When you create a function, OrientDB always binds itself to the orient variable. Using this variable you can call methods to access, query and operate on the database from the function. The specific method called to access the database depends on the type of database you're using:

Function	Description
`orient.getGraph()`	Retrieves the current Transactional Graph Database instance
`orient.getGraphNoTx`	Retrieves the current Non-transactional Graph Database instance
`orient.getDatabase()`	Retrieves the current Document Database instance

For instance, say you wanted a function to create the given user on the database. You might create one that takes three arguments: userName, passwd and roleName.

// Fetch Database
var db = orient.getDatabase();
var role = db.query("SELECT FROM ORole WHERE name = ?", roleName);

if (role == null){
    response.send(404, "Role name not found", "text/plain",
        "Error: Role name not found");
} else {
    db.begin();
    try {
        var result = db.save({"@class", name: userName, password: passwd,
            status: "ACTIVE", roles: role});
            db.commit();
            return result;
    } catch(err){
        db.rollback();
        response.send(500, "Error creating new user", "text/plain",
            err.toString());
    }
}

Methods

As demonstrated in the example above, once you've retrieved the database interface, you can begin to call a series of additional methods to operate on the database from within the function.

Method	Description
`addEdge()`	Adds edges to the graph
`addVertex()`	Adds vertices to the graph
`command()`	Issues SQL command
`delete()`	Removes records
`getEdge()`	Retrieves edges
`getVertex()`	Retrieves vertices
`load()`	Retrieves records
`query()`	Queries the database
`removeEdge()`	Removes edges from a graph
`removeVertex()`	Removes vertices from a graph

Database Methods

Method	Description
`isUseLightweightEdges()`	Check if database uses Lightweight Edges
`open()`	Opens the database
`close()`	Closes the database
`setUseLightweightEdges()`	Enable or disable the use of Lightweight Edges

Class Methods

Method	Description
`browseClass()`	Returns all records in a class
`countClass()`	Counts records in given class
`createEdgeType()`	Creates a new class for edges
`createVertexType()`	Creates a new class for vertices
`dropEdgeType()`	Removes an edge class
`dropVertexType()`	Removes a vertex class
`getEdgeBaseType()`	Retrieves the base class for edges, which is `E` by default
`getEdgeType()`	Retrieves the given edge class
`getVertexBaseType()`	Retrieves the base class for vertices, which is `V` by default
`getVertexType()`	Retrieves the given edge class

Cluster Methods

Method	Description
`browseCluster()`	Returns all records in a cluster
`dropCluster()`	Removes cluster
`getClusterIdByName()`	Retrieves the Cluster ID for the given cluster
`getClusterNameById()`	Retrieves logical cluster name
`getClusterNames()`	Retrieve cluster names
`getClusterRecordSizeById()`	Retrieves the number of records in a cluster
`getClusterRecordSizeByName()`	Retrieves the number of records in a cluster
`getClusters()`	Retrieves clusters

Transaction Methods

Method	Description
`begin()`	Initiates a transaction
`commit()`	Commits a transaction
`isAutoStartTx()`	Checks whether transaction auto-start is enabled
`rollback()`	Reverts a transaction
`setAutoStartTx()`	Enables transaction auto-start

User Methods

Method	Description
`getUser()`	Retrieves the current user
`setUser()`	Sets the user

Size Methods

Method	Description
`countClass()`	Counts records in given class
`countEdges()`	Counts edge records
`countVertices()`	Counts vertex records

Database