FrontBase Documentation

Backtrack:   Welcome!     6. Original Documentation

Updated: 20-Nov-2000 prev — next Table of Contents

6.10. FrontBase EOF Adaptor

The Basic Login Panel

The FrontBase login panel is used to specify the information needed to connect to a FrontBase database. The simplest form of the login panel looks like:


The database name must be specified. Please note that database names are case sensitive, i.e. 'test' denotes a different database than 'TEST'.

The host name specifies the name of the host in the network running the FrontBase database. Please note, that all host names must be entered using lowercase letters only. If no host name is specified the name of the local host is used.

When connecting to the database server it may be required to specify a password, namely if one has been set by the database administrator. If a password is specified, this password will be used to connect to the database server.

The user name specifies the database authorization id. In SQL 92 the authorization id is used for determining access rights and privileges. As the authorization id is an SQL 92 concept it is case insensitive and is converted to uppercase by the login panel. If the user name is not specified, the login name of the host operating system is used (converted to uppercase).

The Cancel button cancels the login panel. The Login button will attempt a login. If the login is unsuccessful an alert panel will pop up and the problem can be corrected and a new login can be attempted.

The Expert Login Panel

If you select the expert option in the basic login panel it will change to:


The expert login panel offers a rich variety of options such that connection to the database server can be adapted to suite the needs of the application.

SQL 92

The catalog name enables you to specify the SQL 92 catalog that is going to be used. If none is specified the catalog name is the same as the database name converted to uppercase letters.

The schema name enables the user to specify the schema to be used. If none is specified the default schema for the authorization id is used.

Debug

If the Debug option is checked the adaptor will print the SQL 92 statements sent to the database server either to the debug log file or to the standard output.

Updatability

If the application never modifies data in the database the Read only option should be checked. The Read only option willimprove the overall performance in the database server.

Isolation level

The isolation level specifies the degree of isolation between transactions:

• Versionized
  
  The version of the database that were in effect when the transaction started is used throughout the transaction, thus the application may access sligthly outdated data, but it will avoid blocking during other transaction updates.
  
  
• Serializable
  
  Locks are placed on tables, allowing one writer and several readers.
  
  
• Repeatable read
  
  Locks are placed on rows, allowing one writer several readers. Please note, that rows may be inserted in the table during the transaction, such that selects may produce a different number of rows.
  
  
• Committed read
  
  No locks are used, however only changes that have been committed can be read.
  
  

Locking discipline

Selects the locking discipline which selects the method used for locking.

• Pessimistic
  
  When a row in the database is updated it is assumed that someone else is going to update it as well, so before the row is updated the application waits for it to be free and locks for the duration of the transaction.
  
  
• Upgradable / deferred
  
  As pessimistic, but all locks are initially read locks and are upgraded to be write locks as needed.
  
  
• Optimistic
  
  As the name suggests the oposite of pessimistic, it is assumed that the application is the only one that updates a row. The transaction will fail if this is not the case.
  
  

Batch sizes

With the Batch sizes option the number of rows fetched from the databases in the first and subsequent fetches can be specified.

Server timeout

If the Server timeouts option is checked the adaptor will at most wait for the specified number of seconds for an answer from the database. If the timeout expires the connection to the database is shut down and the reconnect procedure is started.

If you have feedback or questions on this document, please send e-mail to doc-feedback@frontbase.com. Please reference the section number and topic. Thanks!!

©2000 FrontBase, Inc. All rights reserved.