Oracle® Database Lite Developer's Guide
Part No. B15920-01
The Apache Server is a public domain HTTP server derived from the National Center for Supercomputing Applications (NCSA).
A source of data, either a table or a view, that underlies a view. When you access data in a view, you are really accessing data from its base tables.
Connected is a generic term that refers to users, applications, or devices that are connected to a server. The Mobile client for Web-to-go is "connected" when it is in online mode.
A database object is a named database structure: a table, view, sequence, index, snapshot, or synonym.
The Oracle database server is the third tier of the Mobile Server/Mobile Client Web model. It stores the application data.
Disconnected is a generic term that refers to users, applications, or devices that are not connected to a server. The Mobile client for Web-to-go is "disconnected" when it is in offline mode.
A foreign key is a column or group of columns in one table or view whose values provide a reference to the rows in another table or view. A foreign key generally contains a value that matches a primary key value in another table. See also "Primary Key".
An index is a database object that provides fast access to individual rows in a table. You create an index to accelerate the queries and sorting operations performed against the table's data. You also use indexes to enforce certain constraints on tables, such as unique and primary key constraints.
Indexes, once created, are automatically maintained and used for data access by the database engine whenever possible.
An integrity constraint is a rule that restricts the values that can be entered into one or more columns of a table.
Java applets are small applications that are executed in the browser that extend the functionality of HTML pages by adding dynamic content.
JDBC (Java Database Connectivity) is a standard set of java classes providing vendor-independent access to relational data. Modeled on ODBC, the JDBC classes provide standard features such as simultaneous connections to several databases, transaction management, simple queries, manipulation of pre-compiled statements with bind variables, and calls to stored procedures. JDBC supports both static and dynamic SQL.
JavaServer Pages (JSP) is a technology that enables developers to change a page's layout without altering the page's underlying content. JSP, which uses HTML and pieces of Java code to combine the presentation of dynamic content with business logic.
Java servlets are protocol and platform-independent server-side components that are written in Java. Java servlets dynamically extend Java-enabled servers and provide a general framework for services built using the request-response paradigm.
A relationship established between keys (both primary and foreign) in two different tables or views. Joins are used to link tables that have been normalized to eliminate redundant data in a relational database. A common type of join links the primary key in one table to the foreign key in another table to establish a master-detail relationship. A join corresponds to a WHERE clause condition in a SQL statement.
A master-detail relationship exists between tables or views in a database when multiple rows in one table or view (the detail table or view) are associated with a single master row in another table or view (the master table or view).
Master and detail rows are normally joined by a primary key column in the master table or view that matches a foreign key column in the detail table or view.
When you change values for the primary key, the application should query a new set of detail records, so that values in the foreign key match values in the primary key. For example, if detail records in the EMP table are to be kept synchronized with master records in the DEPT table, the primary key in DEPT should be DEPTNO, and the foreign key in EMP should be DEPTNO. See also "Primary Key" and "Foreign Key".
MIME (Multipurpose Internet Mail Extensions) is a message format used on the Internet to describe the contents of a message. MIME is used by HTTP servers to describe the type of file being delivered.
MIME Type is a file format defined by Multipurpose Internet Mail Extension (MIME).
Mobile client for Web-to-go
The Mobile client for Web-to-go is the client tier of the Web-to-Go model. It contains the Mobile Server and Oracle Database Lite. Web-to-Go replicates the user applications and data to the Mobile device. When the user synchronizes, Web-to-Go replicates any data changes to the Oracle database.
Mobile Development Kit for Web-to-go
The Mobile Development Kit for Web-to-go enables application developers to develop and debug Web-to-go applications that consist of Java servlets, JavaServer Pages (JSP), or Java applets.
The Mobile Server resides on the application server tier of the three-tier Web-to-go model and processes requests from the Mobile client for Web-to-go to modify data in the Oracle database server. The Mobile Server can be configured to run with the Oracle application server or as a standalone Mobile Server.
Mobile Server Repository
The Mobile Server repository is a virtual file system. It is a persistent resource repository that contains all application files and definitions of the applications.
ODBC (Open Database Connectivity) is a Microsoft standard that enables database access on different platforms. You can enable ODBC support on the Mobile client for Web-to-go for troubleshooting purposes. ODBC support enables you to view the client's data, which is stored on the local Oracle Database Lite. To view this information, you can use Mobile SQL.
The Oracle database is the database component of the Mobile Server.
Oracle Database Lite
Oracle Database Lite is a small footprint relational database.
The Packaging Wizard enables administrators to package and publish Mobile applications to the Mobile Server repository. Developers can use the Packaging Wizard to create a new application or to edit an existing application definition.
A positioned DELETE statement deletes the current row of the cursor. Its format is:
DELETE FROM table WHERE CURRENT OF cursor_name
A positioned UPDATE statement updates the current row of the cursor. Its format is:
tableSET set_list WHERE CURRENT OF cursor_name
A table's primary key is a column or group of columns used to uniquely identify each row in the table. The primary key provides fast access to the table's records, and is frequently used as the basis of a join between two tables or views. Only one primary key may be defined per table.
To satisfy a PRIMARY KEY constraint, no primary key value can appear in more than one row of the table, and no column that is part of the primary key can contain a NULL value.
A publication item is a SQL select statement that specifies which data subset a client can access. A publication item usually corresponds to a replica table on the client device. You can create publication items using the Mobile Server Admin API. This API contains Java functions that implement the publish/subscribe model. You can call the functions in this API from within Java programs as standard function calls.
Referential integrity is defined as the accuracy of links between tables in a master-detail relationship that is maintained when records are added, modified, or deleted.
Carefully defined master-detail relationships promote referential integrity. Constraints in your database enforce referential integrity at the database (the server in a client/server environment).
The goal of referential integrity is to prevent the creation of an orphan record, which is a detail record that has no valid link to a master record. Rules that enforce referential integrity prevent the deletion or update of a master record, or the insertion or update of a detail record, that creates an orphan record.
Replication is the process of copying and maintaining database objects in multiple databases that make up a distributed database system. Changes applied at one site are captured and stored locally before being forwarded and applied at each of the remote locations. Replication provides users with fast, local access to shared data, and protects the availability of applications because alternate data access options exist. Even if one site becomes unavailable, users can continue to query or even update the remaining locations.
Replication conflicts occur when contradictory changes to the same data are made.
A schema is a named collection of database objects, including tables, views, indexes, and sequences.
A sequence is a schema object that generates sequential numbers. After creating a sequence, you can use it to generate unique sequence numbers for transaction processing. These unique integers can include primary key values. If a transaction generates a sequence number, the sequence is incremented immediately whether you commit or roll back the transaction.
The sequence window contains a unique range of values. The range of values never overlaps with those of other clients. When a client uses all the values in the range of its sequence window, the Mobile client recreates the sequence with a new, unique range of values.
A snapshot is a subset of application data for a specific user. For each user, the publication (within the application) contains a SQL query that defines the information relevant to this user. This information is known as the snapshot.
The Mobile client retrieves the appropriate data from the Oracle database and downloads to the client before it goes offline. A snapshot can be a copy of an entire database table, or a subset of rows from the table. The first time a user synchronizes, the Mobile client automatically creates the snapshots on the client machine. Each subsequent time that a user synchronizes, the Mobile client either refreshes the snapshots with the most recent data or recreates them depending on the complexity of the snapshot.
SQL, or Structured Query Language, is a non-procedural database access language used by most relational database engines. Statements in SQL describe operations to be performed on sets of data. When a SQL statement is sent to a database, the database engine automatically generates a procedure to perform the specified tasks.
Synchronization is the process the Mobile client uses to replicate data between the Mobile client and the Oracle database. The Mobile client replicates the user applications and data to Oracle Database Lite when the user synchronizes. The Mobile client replicates any data changes made on the client to the Oracle database.
A synonym is an alternative name, or alias, for a table, view, sequence, snapshot, or another synonym.
A table is a database object that stores data that is organized into rows and columns. In a well designed database, each table stores information about a single topic (such as company employees or customer addresses).
Three-Tier Web Model
The three-tier Web model is an Internet database configuration that contains a client, a middle tier, and an Oracle database server. Web-to-go architecture follows the three-tier Web model.
A set of changes made to selected data in a relational database. Transactions are usually executed with a SQL statement such as INSERT, UPDATE, or DELETE. A transaction is complete when it is either committed (the changes are made permanent) or rolled back (the changes are discarded).
A transaction is frequently preceded by a query, which selects specific records from the database that you want to change. See also "SQL".
A table's unique key is a column or group of columns that are unique in each row of a table. To satisfy a UNIQUE KEY constraint, no unique key value can appear in more than one row of the table. However, unlike the PRIMARY KEY constraint, a unique key made up of a single column can contain NULL values.
A view is a customized presentation of data selected from one or more tables (or other views). A view is like a "virtual table" that allows you to relate and combine data from multiple tables (called base tables) and views. A view is a kind of "stored query" because you can specify selection criteria for the data that the view displays.
Views, like tables, are organized into rows and columns. However, views contain no data themselves. Views allow you to treat multiple tables or views as one database object.
Oracle Web-to-go is a framework for the creation and deployment of Mobile, Web-based, database applications. Web-to-go contains a three-tier database architecture consisting of the Mobile client for Web-to-go, the Mobile Server and Oracle database. It is centrally managed from the server and Web-to-go applications can be run when Web-to-go connected to the server (online) or disconnected from the server (offline). When Web-to-go is offline it caches data locally and synchronizes the data with the server when it goes back online.
The Mobile Server Workspace is a Web page that provides users with access to Web-to-go applications. Web-to-go generates the Workspace in the user's browser after the user logs in to Web-to-go. The Workspace displays icons, links, and descriptions of all applications that are available to the user. An application is available to the user after the administrator publishes it to the Web-to-go system and grants access privileges to the user.