Overview of Content Management Features
Oracle includes datatypes to handle all the types of rich Internet content such as relational data, object-relational data, XML, text, audio, video, image, and spatial. These datatypes appear as native types in the database. They can all be queried using SQL. A single SQL statement can include data beloging to any all of these datatypes.
Overview of Security Features
The Oracle database provides discretionary access control, which is a means of restriction access to information based on privileges. The appropriate privilege must be assigned to a user in order for that user to access a schema object. Appropriately privileged users can grant other users privileges at their discretion.
Oracle manages database security using several different facilities:
- Authentication to validate the identity of the entities using your networks, database, and applications
- Authorization processes to limit access and actions, limits that are linked to user's identities and roles.
- Access restrictions on objects, like tables or rows.
- Security policies
- Database auditing
Overview of Data Integrity and Triggers
Data must adhere to certain business rules, as determined by the database administrator or application developer. Oracle provides integrity constraints and database triggers to manage data integrity rules.
Integrity Constraints An integrity constraint is a declarative way to define a business rule for a column of a table. The following integrity constraints are supported by Oracle:
- NOT NULL: Disallows nulls (empty entries) in a table's column.
- UNIQUE KEY: Disallows duplicate values in a column or set of columns.
- PRIMARY KEY: Disallows duplicate values and nulls in a column or set of columns.
- FOREIGN KEY: Requires each value in a column or set of columns to match a value in a related table's UNIQUE or PRIMARY KEY. FOREIGN KEY integrity constraints also define referential integrity actions that dictate what Oracle should do with dependent data if the data it references is altered.
- CHECK: Disallow values that do not satisfy the logical expression of the constraint.
Keys Key is used in the definitions of several types of integrity constraints. A key is the column or set of columns included in the definition of certain types of integrity constraints. The different types of keys include:
- Primary key: The column or set of columns included in the definition of a table's PRIMARY KEY constraint. A primary key's values uniquely identify the rows in a table. Only one primary key can be defined for each table.
- Unique key: The column or set of columns included in the definition of a UNIQUE constraint.
- Foreign key: The column or set of columns included in the definition of a referential integrity constraint.
- Referenced key: The unique key or primary key of the same or a different table referenced by a foreign key.
Triggers
Triggers are procedures written in PL/SQL, Java, or C that run (fire) implicitly whenever a table or view is modified or when some user actions or database system actions occur.
Overview of Information Ingegration Features
A distributed environment is a network of disparate systems that seamlessly communicate with each other. Each system in the distributed environment is called a node. The system to which a user is directly connected is called the local system. Any additional systems accessed by this user are called remote systems. A distributed environment allows applications to access and exchange data from the local and remote systems. All the data can be simultaneously accessed and modified.
Distributed SQL An Oracle distributed database system can be transparent to users, making it appear as though it is single Oracle database. Companies can use this distributed SQL feature to make all its Oracle database look like one and thus reduce some of the complexity of the distributed system. Oracle uses database links to enable users on one database to access objects in a remote database. A local user can access a link to a remote database without having to be a user on the remote database.
Oracle Streams Oracle Streams enables the propagation and management of data, transactions, and events in a data stream either within a database, or from one database to another. The stream routes published information to subscribed destinations. As users' needs change, they can simply implement a new capability of Oracle Streams, without sacrificing existing capabilities.
Oracle Streams provides a set of elements that lets users control what information is put into a stream, how the stream flows or isrouted from node to node, what happens to events in the stream as they flow into each node, and how the stream terminates. By specifying the configuration of the elements acting on the stream, a user can address specific requirements, such as message queuing or data replication.
Oracle Transparent Gateways and Generic Connectivity Oracle Transparent Gateways and Generic Connectivity extend Oracle distributed features to non-Oracle systems. Oracle can work with non-Oracle data sources, non-Oracle message queuing systems, and non-SQL applications, ensuring interoperability with other vendor's products and technologies.
They translate third party SQL dialects, data dictionaries, and datatypes into Oracle formats, thus making the non-Oracle data store appear as a remote Oracle database. These technologies enable companies to seamlessly integrate the different systems and provide a consolidated view of the company as a whole.
Oracle Transparent Gateways and Generic Connectivity can be used for synchronous access, using distributed SQL, and for asynchronous access, using Oracle streams. Introducing a Transparent Gateway into an Oracle Streams environment enables replication of data from an Oracle databaase to a non-Oracle database.