Multi-Session Operation

Access Manager has always supported multiple users, but since Version 2.20 it has allowed multiple users to log in at the same time. The former is called exclusive operation, whereas the latter is called multi-session operation. If your requirement is only ever going to be one user viewing the database at a time, it is recommended that you create an exclusive database as you will find it faster and simpler to maintain (there being just one database file which is entirely maintained by Access Manager). Multi-session operation requires the installation and use of a database server. Each Access Manager session is linked to the database server using Open Database Connectivity (ODBC), which provides a degree of flexibility in the choice of database server.

Access Manager Sessions

With an exclusive database there can only ever be one Access Manager session. It is either online and can therefore communicate with the EasyOpen hardware, or it is offline and cannot. When there are multiple sessions only one can be online and communicating with the hardware, but providing there is at least one session online all the other sessions will behave as if they communicating directly with the hardware. The only thing the other sessions can't do is go online or offline (because they have no hardware attached to set online or offline). The online session is the primary session, whilst all the other sessions are secondary sessions. Note that if the hardware is connected via a LAN or WAN, any session can become a primary session provided the PC on which it is running has the correct drivers installed. If you want to work this way you must ensure that the RS485 server is set up to allow one connection at a time, otherwise multiple sessions will attempt to become the primary session and communication with the hardware will be chaotic.

A Suggested Setup

You will probably find it simplest to have a single PC set up to run the primary session (ie it will be the only PC with the necessary drivers), and have that PC running the primary session all the time. Unless your database server is acting as a server for other (critical) applications, it is best to run the primary session and the database server on the same PC.   For maximum convenience and reliability you will probably want to run the primary session as a service.

The tag allocation reader can either be a USB-connected reader or a controller-connected reader as normal, but tag scanning can be carried out from either the primary session or a secondary session. The best options are either to use a USB-connected reader attached to the PC used for tag scanning, or if using a controller-connected reader to scan the tags using the primary session.

Database Servers

A database server is an application which provides database services for other applications. There are many such applications, but Access Manager works with Firebird Superserver (not Classic Server), MySQL, and PostgreSQL. It may work with other backend database servers, but since they each have their own dialects this is by no means certain.

In addition to the database server each client PC will need an appropriate ODBC driver. This often comes free with the server (usually in a separate download), but commercial third-party drivers are available also.

Details of how to set up and maintain a database server are beyond the scope of this Help; you should consult the relevant documentation for the server. In general you need to be able to:

• Create, delete and edit database users.
• Create a database and set the access rights to it.
• Compact a database.
• Backup a database.
• Delete a database.

However, some helpful hints are given here which should help you get started.

Firebird

Access Manager is shipped with Firebird and is most closely integrated with Firebird. The File Wizard (which runs when Access Manager first starts, or if you select File...New from the menu) allows you to create a suitable new Firebird database on any Firebird server. To do this you need to have an account on the server. Firebird is installed with a default administrative account SYSDBA. According to the Firebird Quick Start guide:

This account has all the privileges on the server and cannot be deleted. Depending on version, OS, and architecture, the installation program will either

• install the SYSDBA user with the password masterkey (actually, masterke: characters after the eighth are ignored), or
• ask you to enter a password during installation, or
• generate a random password and store that in the file SYSDBA.password within your Firebird installation directory.

If the password is masterkey and your server is exposed to the Internet at all – or even to a local network, unless you trust every user with the SYSDBA password – you should change it immediately using the gsec command-line utility. Go to a command shell, cd to the Firebird bin subdirectory and issue the following command to change the password to (as an example) icuryy4me:

gsec -user sysdba -pass masterkey -mo sysdba -pw icuryy4me

Notice that you specify “sysdba” twice in the command:

• With the -user parameter you identify yourself as SYSDBA. You also provide SYSDBA's current password in the -pass parameter.
• The -mo[dify] parameter tells gsec that you want to modify an account – which happens to be SYSDBA again. Lastly, -pw specifies the type of modification: the password.

If all has gone well, the new password icuryy4me is now encrypted and stored, and masterkey is no longer valid. Please be aware that unlike Firebird user names, passwords are case-sensitive.

The Quick Start guide then goes on to tell you how to create additional database server users.

If you need to run multiple Firebird clients on one PC, and the default client is not the one Access Manager should be using, you should copy the correct version of fbclient.dll to the Access Manager program folder. This is an advanced topic and further information on running multiple server versions on one PC is beyond the scope of this document.

MySQL

You can create a provisional MySQL database using the mysql command line tool as follows:

• create database userinfo default character set latin1;
  Creates a database called userinfo with Windows Western European character set.
• grant all on userinfo.* to 'root'@'client';
  Grants all rights to all parts of database userinfo to user root.
• drop database userinfo;
  Destroys the database called userinfo.

Note that when creating the database proper you should create at least one user with a robust password or your database will be vulnerable to hacking.

PostgreSQL

The initial setup of PostgreSQL for Windows is integrated into the installer. There is a lot to do but it is fairly straightforward. pgAdmin can then be used to manage the database and users.

The initial setup of PostgreSQL for Linux is quite complicated and well beyond the novice user, as it requires manual editing of various configuration files. Even an experienced Linux user will need to seek out instructions on the internet. In brief you will need to:

• Create a database administrative user (most administrators give this user the username postgres).
• As the administrative user you need to initialise the data directory using initdb.
• Edit postgresql.conf to set tcpip_socket to true.
• Edit pg_hba.conf to include the line host all all aaa.bbb.ccc.ddd 255.255.255.255 trust, where aaa.bbb.ccc.ddd is the IP address of the client PC.
• Start the server using pg_ctl (you will probably want to automate this using a suitable entry in init.d).
• Create a database user using createuser.
• Create a database using createdb.

You will need to Vacuum the database regularly, and of course have a proper backup strategy.

Database Server Comparison

The following information is likely to become out of date, so you are advised to check any database server that you think meets your requirements. You will find that performance may vary dramatically depending on the operating system and whether the server and primary session are on the same PC or not. A newer, faster PC will not necessarily outperform an older PC running a different operating system. To help you compare database servers, a database speed index tool can be found under the Access Manager Help menu.

Open Database Connectivity

Open Database Connectivity (ODBC) is a technology that allows a database client PC to talk to a database server even if the two machines are not running the same operating system. To a degree it also allows the client PC to talk to completely different database server engines. Each client PC needs to run an ODBC driver suitable for the intended database server engine. There should be no problem running multiple ODBC drivers on a client PC if that is necessary.

When a client PC connects to a server the ODBC driver needs to be given the details of the connection. The Access Manager File Wizard (which runs when Access Manager first starts, or if you select File...New from the menu) will gather some basic information from you and use it to create the connection details. Alternatively you can ask the Wizard to let you use the Windows ODBC connection manager, but you will find you will have to enter not only the basic information that the File Wizard would have asked for, but also some rather obscure details.

The connection information is stored in one of three ways:

• Privately (Microsoft call this a user data source).
  The information gathered will only be accessible to user(s) who can log in to the Windows account under which the data was gathered. Anyone else would have to re-enter the information. The password may or may not be saved in an encrypted form, depending on which ODBC driver is used.
• Publicly (Microsoft call this a machine data source).
  The information will be accessible to anyone who has a Windows account on the client PC. Users on other client PCs would have to re-enter the information. The password may or may not be saved in an encrypted form, depending on which ODBC driver is used.
• In a file (Microsoft call this a file data source).
  The information will be accessible to anyone who has access to the file. This has the great benefit that the information need only be entered once. Since this information includes a password, Access Manager will encrypt the password before saving it in the file, but only if you use the Wizard to gather the information. The password will not be encrypted if you use the Windows ODBC connection manager.

Windows ODBC Connection Manager (Advanced)

If you elect to use the Windows ODBC connection manager, you will need to consult the table of data source connection settings, or your connection will be problematic.