|Oracle® Database Lite Administration and Deployment Guide
Part Number B28922-01
Connected is a generic term that refers to users, applications, or devices that are connected to a server.
A database object is a named database structure: a table, view, sequence, index, snapshot, or synonym.
The database server is the third tier of the Mobile Server three-tier 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.
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 queries and sorting operations performed against the table's data. Indexes can also be used 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.
JavaServer Pages (JSP) is a technology that enables developers to change a page's layout without altering the page's underlying content. JSP 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.
Java Server Development Kit
The Java Servlet Development Kit is a tool provided by Sun Microsystems for developing Java servlets.
Java Web Server Development Kit
The Java Web Server Development Kit 1.0.1 is a Sun Microsystems tool for developing both JavaServer Pages (JSP) and Java servlets.
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.
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 an SQL statement.
The leapfrog sequence is one of two sequence types that Web-to-Go uses in order to provide unique primary key values to the Mobile client for OC4J or Web-to-Go. Leapfrog sequences contain a different start value for each client, and each sequence increment is set to a larger value than the maximum number of clients.
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.
Mobile client for OC4J or 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 Manager is a Mobile application that runs in the browser for easy administration of applications and users. Administrators use the Mobile Manager to perform such functions as granting or revoking application access to users or groups, modifying snapshot template variables, or deleting applications from the Mobile Server.
The Mobile Server resides on the application server tier of the three-tier Mobile Server model and processes requests from Mobile Clients to modify data in the database server.
Mobile Server Repository
The Mobile Server Repository is a virtual file system that resides on Oracle. 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 OC4J or Web-to-Go for troubleshooting purposes. ODBC support enables you to view the client's data, which is stored on a local Oracle Lite database. To view this information, you can use SQL*Plus.
Oracle is the database component of the Mobile Server. When the Mobile client for OC4J or Web-to-Go is connected, it stores applications and data on Oracle.
Oracle Lite is the database component of the Mobile client for OC4J or Web-to-Go. When the client is disconnected from the back-end Oracle server, it stores applications and data in the client Oracle Lite database.
The Packaging Wizard enables developers to define and package new or existing Mobile Server applications.
DELETE statement deletes the current row of the cursor. Its format is as follows:
DELETE FROM table WHERE CURRENT OF cursor_name
UPDATE statement updates the current row of the cursor. Its format is as follows:
UPDATE table SET 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
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.
The registry contains a unique Web-to-Go name/value pairs. All registry names must be unique.
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. Replication conflicts can be avoided by proper subsetting of data. The Packaging Wizard allows the developer to specify rules on how to handle conflicts.
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.
Web-to-Go creates a database for each user on the Mobile client for OC4J or Web-to-Go. This database is called a site. A client can contain multiple sites, but only one site per user. Users can have multiple sites on different clients.
Snapshots are copies of application data that Web-to-Go captures in real-time from the Oracle database and downloads the same to the client. A snapshot can be a copy of an entire database table, or a subset of rows from the table. When you define your snapshot, you can use the
WHERE clause to specify a parameterized SQL query, where only the row data that your application uses is downloaded to the client. Thus, you can define what is downloaded to the client: the entire contents of the table or the subset of information that is relevant to the specific user. Most applications specify a particular subset of data that is relevant only to the user to be downloaded.
Web-to-Go automatically creates the snapshots on the client machine. Each subsequent time that a user goes connects through synchronization, Web-to-Go 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.
SQL*Plus is a tool that connects to an Oracle Lite database and accesses data. You must have ODBC support enabled to use SQL*Plus.
Synchronization is the process Web-to-Go uses to replicate data between the Mobile client for OC4J or Web-to-Go and Oracle. Web-to-Go replicates (downloads) the user applications and data to Oracle Lite from the back-end Oracle database, based upon the SQL query defined in the publication. In addition, all modifications made on the client are uploaded to the Oracle server, if the publication is defined as updateable and not as read-only.
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 a 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
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
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, the Mobile Server and Oracle. It is centrally managed from the server and Web-to-Go applications can be run when Web-to-Go is connected to the server or disconnected from the server. When Web-to-Go is disconnected, it stores data locally in the Cache folder and synchronizes data with the server, when it reconnects.
Mobile client for OC4J or Web-to-Go
The Mobile client for OC4J or Web-to-Go is the client tier of the Web-to-Go three-tier Web model. It contains the Mobile Server and the Oracle Lite database. Web-to-Go replicates the user applications and data to Oracle Lite database. If the publication is updateable and changes are made on the client, then Web-to-Go replicates any data changes to the back-end Oracle database.
The window sequence is one of two sequences Web-to-Go uses in order to provide unique primary key values to the Mobile client for OC4J or Web-to-Go. The window sequence 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, Web-to-Go recreates the sequence with a new, unique range of values.
The Mobile Server Workspace is a Web page that provides users with access to OC4J or Web-to-Go applications. OC4J or Web-to-Go generates the Workspace in the user's browser after the user logs in. 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.