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BasicUsage.md

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Basic usage

Driver's public API with its core functionality is exposed through Arango.Client namespace. Most of the classes which perform operations on ArangoDB database starts with A prefix (e.g. ADatabase, ACollection, AQuery, ...) to reduce the visual noise of superfluous naming.

Connection management

Before the connection is initiated, driver needs to know database address, name and credentials (if needed) which will be stored under specified alias. ASettings static class provides several static methods which are used to manage connection data about remote database backends.

// adds new connection data to database manager
ASettings.AddConnection(
    "myDatabaseAlias",
    "127.0.0.1",
    8529,
    false,
    "myDatabase",
    "usr",
    "pwd"
);

Checking and removing existing connections

Existing connections can be checked and removed with HasConnection and RemoveConnection methods exposed through ASettings static class.

// checks if the specific connection stored under specific alias exists
if (ASettings.HasConnection("someDatabaseAlias"))
{
    // removes specified connection
    ASettings.RemoveConnection("someDatabaseAlias");
}

Database context

Previously set database alias is used for the purpose of retrieving data needed for connecting to specific database and performing desired operations. There is no need to dispose ADatabase instance in order to free database connection because operations are performed through HTTP calls.

// initialize new database context
var db = new ADatabase("myDatabaseAlias");

// retrieve specified document
var getResult = db.Document.Get("myCollection/123");

AResult object

Once the operation is executed, returned data are contained within AResult object which consists of following properties:

  • Success - Determines whether the operation ended with success and returned result value is other than null.
  • StatusCode - Integer value of the operation response HTTP status code.
  • HasValue - Determines if the operation contains value other than null.
  • Value - Generic object which type and value depends on performed operation.
  • Error - If operation ended with failure, this property would contain instance of AError object which contains further information about the error.
  • Extra - Document which might contain additional information on performed operation.

AError object

In case of operation failure driver doesn't throw exceptions explicitely, but AResult object Error property would contain instance of AError object with following properties:

  • StatusCode - Integer value of the operation response HTTP status code.
  • Number - Integer value indicating ArangoDB internal error code.
  • Message - String value containing error description.
  • Exception - Exception object with further information about failure.

JSON representation

JSON objects are by default represented as Dictionary<string, object>. In order to simplify the usage of dictionaries (aka documents), driver comes equipped with embedded dictator library which provide helpful set of methods to provide easier way to handle data stored in these objects. Dictator also provides methods for conversion of documents to generic objects and vice versa. Custom classes can also take advantage of several property attributes.

Internal serialization and deserialization of JSON documents is done by embedded fastJSON library which functionality is accessible through Arango.fastJSON namespace.

Serialization options

ASettings.JsonParameters static property can be used to set custom serialization options which are provided by fastJSON library. By default all options are set to their default values except UseEscapedUnicode and UseFastGuid which are both set to false value. Advantage of this approach is the ability to, for example, explicitely set UseValuesOfEnums to true value which will result in Enum type fields being stored as integers instead of strings.

Document ID, key and revision

Apart from standard dictionary extensions provided by dictator, there are also following ArangoDB specific extension methods which can be used by Dictionary<string, object> instances to work with ArangoDB standard ID, key and revision document fields:

  • HasID() - Checks if _id field is present and has valid format.
  • ID() - Retrieves value of _id field. If the field is missing or has invalid format null value is returned.
  • ID(string id) - Stores _id field value.
  • HasKey() - Checks if _key field is present and has valid format.
  • Key() - Retrieves value of _key field. If the field is missing or has invalid format null value is returned.
  • Key(string key) - Stores _key field value.
  • HasRev() - Checks if _rev field is present and has valid format.
  • Rev() - Retrieves value of _rev field. If the field is missing or has invalid format null value is returned.
  • Rev(string rev) - Stores _rev field value.
  • IsID(string fieldPath) - Checks if specified field path has valid document ID value in the format of collection/key.
  • IsKey(string fieldPath) - Checks if specified field path has valid document key value.

ADocument class provides several static methods for format validation of ID, key and revision values:

  • ADocument.IsID(string id) - Determines if specified value has valid document _id format.
  • ADocument.IsKey(string key) - Determines if specified value has valid document _key format.
  • ADocument.IsRev(string id) - Determines if specified value has valid document _rev format.
  • ADocument.Identify(string collection, long key) - Constructs document ID from specified collection and key values.
  • ADocument.Identify(string collection, string key) - Constructs document ID from specified collection and key values. If key format is invalid null value is returned.
  • ADocument.ParseKey(string id) - Parses key value out of specified document ID. If ID has invalid value null is returned.

Fluent API

Driver is heavily using fluent API which provides extensive flexiblity to the way how various operations can be executed. Instead of having multiple overloaded methods with bloated set of parameters which can be assigned to given operation, fluent API gives developers ability to apply specific parameter only when needed without the need to obey method signature.

// initialize new database context
var db = new ADatabase("myDatabaseAlias");
// operation core
var queryOperation = db.Query
    .Aql("FOR item IN myCollection RETURN item");

// add optional parameter
if (... condition whether to use count query parameter ...)
{
    queryOperation.Count(true);
}

// add another optional parameter
if (... condition whether to use batch size query parameter ...)
{
    queryOperation.BatchSize(1);
}

// execute query operation
var queryResult1 = queryOperation.ToList();

// more concise example of query operation
var queryResult2 = db.Query
    .Count(true)
    .BatchSize(1)
    .Aql("FOR item IN myCollection RETURN item")
    .ToList();