Aliases

1. Introduction

ll connections to a Dataphor Server begin with the process of selecting an alias. Aliases provide a named connection configuration for a Dataphor Server. They allow for the management of different connection configurations on a given client machine, or for different users on the machine. There are two types of aliases, in-process, and out-of-process.

In-processIn-process aliases allow for the configuration of a complete Dataphor Server instance to be hosted within the client process. Typically, an in-process alias is used when connecting with Dataphoria in development scenarios.

Out-of-processOut-of-process aliases allow for connection to an existing Dataphor Server instance. The instance can be hosted in a Windows Service, or an in-process instance in Dataphoria running on the same machine, or another machine on the network.

Both types of aliases include session configuration information, which supplies the credentials for the user and governs the behavior of the session. Once the session has been established, changing these settings has no effect. The System library provides operators for manipulating the configuration settings of an open session where appropriate.

Each alias is specified as either a machine-specific alias, or a user-specific alias. If a given user-specific alias has the same name as a machine-specific alias, the user-specific alias will be used.

Dataphoria and the Frontend Clients provide the ability to select an alias using the Connect To Server dialog: image::../Images/DataphorServerLogin.bmp[Dataphoria Server Login]

This interface provides for the selection and management of server aliases. It also functions as a login screen, allowing the default credentials specified in the alias to be given. Clicking Add…​ or Edit…​ displays the alias edit screen.

Dataphoria Server Alias Edit

2. Session Information

The configuration information for a session is specified through a set of properties available on both types of aliases. Clicking the Advanced >> button on the alias edit screen provides access to these properties.

Property Description

DefaultIsolationLevel

Determines the default isolation level setting for processes started on this session.

DefaultLibraryName

Determines the default library for the session. If specified, the current library for the session is initially set to this value.

DefaultMaxCallDepth

Determines the default maximum call depth for processes on this session. The default value is 1024.

DefaultMaxStackDepth

Determines the default maximum stack depth for processes on this session. The default value is 32767.

DefaultUseDTC

Determines the default UseDTC setting for processes started on this session. Defaults to false.

DefaultUseImplicitTransactions

Determines the default UseImplicitTransactions setting for processes started on this session. Defaults to true.

FetchAtOpen

Determines whether or not the CLI will fetch as part of the open call.

FetchCount

Determines the number of rows which will be buffered by the CLI. A FetchCount of 1 effectively disables row buffering.

Password

Password used to login to the Dataphor Server. The default login for the Dataphor Server is Admin with a blank password.

UsePlanCache

Determines whether or not to use the server plan cache on this session.

UserID

User ID used to login to the Dataphor Server. The default login for the Dataphor Server is Admin with a blank password.

2.1. User Credentials

The UserID and Password properties specify the security credentials used to login to the Dataphor Server. These are defaults for the server alias, and are overridden by the information provided by the connecting user in the Dataphor Server Login screen. These values are only used to connect if the alias is used explicitly by the client, bypassing the login screen.

The default UserID and Password for a Dataphor Server instance is Admin, blank. Alphora recommends changing this default, and safeguarding the administrative password, as it allows a user complete access to a Dataphor Server.

2.2. Default Library Name

The DefaultLibraryName setting determines the initial current library for the session. Once the session has been established, changing this setting will have no effect. Setting the current library for a session is accomplished using the SetLibrary operator. The current library name for the current session can be retrieved using the LibraryName operator with no parameters.

The current library is used to determine the name resolution path for the session, which is used in the name resolution process. The current library is also the default container for newly created catalog objects. For more information on libraries in D4, refer to the Working with Libraries chapter in the Logical Application Design part of the Dataphor Developer’s Guide.

The default value for this setting is blank, meaning that the Dataphor Server will select a suitable default current library. Typically, the Dataphor Server selects the General library for this purpose.

3. Out-Of-Process Aliases

Aliases

An out-of-process server alias indicates that the client will connect to an existing Dataphor Server instance. The Dataphor Server may be located in another process on the same machine, on another machine on the network, or even on the internet.

Dataphoria Server Alias Edit

The server alias for an out-of-process connection only needs to specify a host name, and a port number. The host name is the name of the machine on which the Dataphor Server is running, and the port number is the TCP/IP port on which the server is listening for connections. The port number for a Dataphor Server instance can be configured on the In-Process alias, or using the Service Configuration Utility when the instance is hosted within a Microsoft Windows Service. The default port number for a Dataphor Server instance is 8061.

4. In-Process Aliases

An in-process server alias indicates that a new Dataphor Server instance should be hosted within the client process. This mechanism is typically used by Dataphoria to provide a convenient development environment, but can also be used in some advanced deployment scenarios.

In addition to session configuration information, in-process aliases have several properties for server-level configuration:

Dataphoria Server Alias Edit In Process

The port number setting specifies the TCP/IP port on which the new Dataphor Server instance will listen for connections. The default port number is 8061.

The catalog directory setting specifies a directory that the Dataphor Server instance will use to save and load catalog information. If the catalog directory is unspecified, the Dataphor Server will create a Catalog directory in the executable directory of the instance.

The library directory setting specifies the directory, or directories that the Dataphor Server instance will use to search for available libraries. Use semi-colons to delimit additional library directories. Each sub-directory of these directories with the appropriate files will be considered an available library in the Dataphor Server. If the catalog indicates that a given library was loaded when the server last started, the library will be loaded at startup. Note that libraries may be attached from any directory accessible by the Dataphor Server, these directories simply specify the default paths that will be searched to display available libraries.

For more information on the System Catalog, refer to the Catalog Elements chapter of the D4 Language Guide in the Dataphor Developer’s Guide. For more information on Libraries, refer to the Working with Libraries chapter in the Logical Application Design part of the Dataphor Developer’s Guide.

Tracing enabled indicates whether internal tracing of server events is enabled. Log errors indicates whether the Dataphor Server will log exceptions that are returned to clients across the CLI boundary.

The Embedded option indicates whether or not this instance of the Dataphor Server will be available to other processes. If the Embedded option is set, the instance will only be available within the process creating the instance. Otherwise, the instance will be available for external connections, either from other processes running on the same machine, or remote processes running on different machines.

The Catalog Store Database Name and Password indicate the name and authentication information for the file used to store the database catalog.

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