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Oracle® Database Lite Oracle Lite Client Guide Release 10.3 Part Number E12548-02 |
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# 1 The Oracle Database Lite RDBMS

The following sections describe the Oracle Database Lite Relational Database Management System (RDBMS):

- Section 1.1, "Oracle Lite Database Overview"

- Section 1.2, "Execution Models for Applications that Use the Oracle Lite Database"

## 1.1 Oracle Lite Database Overview

The Oracle Lite database is compliant to the SQL92 standard and compatible to Oracle databases. In addition, it is compliant to the ACID requirements for transaction support. Because it is a small database specifically designed for a client device, it has a small footprint and is easy to administer. The Oracle Lite database can be installed on the following platforms: Linux, UNIX, Windows (Win32) and WinCE platforms.

You can use the Oracle Lite database that contains client data in a file with an ODB extension; any BLOB objects—either binary or character—and the indexes are stored in a file with an OBS extension. The Oracle Lite database exists solely to store and retrieve the user data specific to this device. It is not a replication of the entire Oracle database.

Because BLOB data and indexes are stored in an OBS file, there is no limit for BLOB data or indexes. The limitation for BLOB data and indexes is the space limitations of the operating system or 16 terabytes. There still exists a 4 GB limitation for the ODB file; however, this is not as much of an issue now that BLOB data can be stored in the OBS files.

Note:

If you have been using the Oracle Lite database prior to the 10.3 release, you can upgrade your database to remove all BLOB data from within it and transfer the BLOB objects to OBS files by using the `defragdb` utility, which is documented in Section C.7, "DefragDB to Defragment and Reduce Size of the Oracle Lite Database".

The Oracle Lite database is an RDBMS that supports ODBC, JDBC, ADO.NET and SODA interfaces. SODA is an Oracle Database Lite specific C++ object API created to access the Oracle Lite database. SODA provides access to SQL as well as object-oriented functionality. See Chapter 8, "Oracle Database Lite Data Access APIs" for more information on each language.

## 1.2 Execution Models for Applications that Use the Oracle Lite Database

When building an application that only uses the Oracle Lite database, you can build it for one of the following purposes:

- For an application that uses the Oracle Lite database to store data solely for a single application, use the embedded application option. See Section 1.2.1, "Embedded Application in Single Process" for more information.

- You can design an application where the data is stored in a back-end Oracle database, but only the data that the user needs to see or update is downloaded to the client device. When either side modifies the data, it is synchronized between the client device and the back-end database. See Section 1.2.2, "Mobile Option for a Client in a Single Process" for more information.

- For multiple applications accessing the same database, use the client/server option. See Section 1.2.3, "Multiple Processes Accessing the Same Database" for more information.

- For any application that accesses the database remotely, use the client/server option. See Section 1.2.4, "Multiple Embedded Application Clients Accessing Remote Database" for more information.

- For an application that must access the database remotely and include the ability to synchronize the client data using Branch Office. See Section 1.2.5, "Multiple Clients Accessing Remote Database" for more information.

### 1.2.1 Embedded Application in Single Process

Figure 1-1 demonstrates an application that embeds the Oracle Lite database within the application. When the application is launched, the Oracle Lite database libraries are loaded into the same process as the application.

Figure 1-1 Embedded Application With ODB Libraries in Single Process

Description of "Figure 1-1 Embedded Application With ODB Libraries in Single Process"

See Chapter 4, "Building an Embedded Application" for more information on how to embed an Oracle Lite database into an application.

### 1.2.2 Mobile Option for a Client in a Single Process

If you chose to install the Mobile client and synchronized your user on a single device, then when you launch your application, the Oracle Lite database libraries are loaded into the same process as your application. This scenario is demonstrated in Figure 1-2.

Figure 1-2 Diagram of Mobile Client and ODB Libraries in SIngle Process

Description of "Figure 1-2 Diagram of Mobile Client and ODB Libraries in SIngle Process"

For details of how to create a Mobile application using the Oracle Lite database, see Section 2.2, "Creating and Managing the Database for a Mobile Client" in the Oracle Database Lite Administration and Deployment Guide.

### 1.2.3 Multiple Processes Accessing the Same Database

Figure 1-3 shows how you can configure multiple application processes to share the same database on the same machine. Thus, when each application is launched, each application exists in its own process and can access the same database independently. In this scenario, Oracle Database Lite libraries use shared memory to coordinate locking between both processes.

Figure 1-3 Applications in Multiple Processes Accessing Single Database

Description of "Figure 1-3 Applications in Multiple Processes Accessing Single Database"

For more details, see Chapter 4, "Building an Embedded Application".

Note:

This scenario is not available on WinCE.

### 1.2.4 Multiple Embedded Application Clients Accessing Remote Database

If you are embedding a database into your application software, but you want the applications to be located on clients that are remote from the data within the Oracle Lite database, then use the client/server embedded approach with the multi-user service, as described in Chapter 5, "Building a Client/Server Environment".

### 1.2.5 Multiple Clients Accessing Remote Database

If you have several remote clients accessing the same data, you can use Branch Office to facilitate the remote applications. Figure 1-4 demonstrates how multiple remote Branch Office clients access the data through the Branch Office machine to the Mobile Server and finally accessing the back-end Oracle database.

The Branch Office machine contains the Branch Office executables and the local Oracle Lite database, which all clients access for their information. When a synchronization is requested, information is communicated between the Branch Office and the back-end database through the Mobile Server.

Note:

Oracle Database Lite is not identical to the Oracle database; thus, it is not designed for large amounts of transferred data or a large number of concurrent transactions.

Figure 1-4 Using Branch Office for Managing Multiple Clients that Access a Remote Database

Description of "Figure 1-4 Using Branch Office for Managing Multiple Clients that Access a Remote Database"

See Chapter 9, "Manage Your Branch Office" in the Oracle Database Lite Administration and Deployment Guide for more information.