(Les01 Architecture I) [20180109], les0120180109

(Les01 Architecture I) [20180109], les0120180109
Objective: To learn more: Oracle Database main structural component-Parsing Memory Structure-describing database background processes-association between logical and physical storage structures-Description of ASM storage component Oracle database-processing as a unit. -The purpose of a database is to store and retrieve relevant information. -The Oracle relational database management system (RDBMS) reliably manages a large amount of data in a multi-user environment so that multiple users can access the same data at the same time. This is done with high performance. -It can prevent unauthorized access and provide effective solutions for fault recovery. Method 1: log on to the operating system of the Oracle instance and enable the database access application or tool. The communication path is created using the available inter-process communication mechanism on the host operating system. Method 2: Start an application or tool on your local computer and connect to the operating system running the Oracle database through the network. (Client/Server) connects the front-end (Customer Service) and backend (server) through the network ). Method 3: The user accesses the application service through a local tool (such as WEB), and the application server proxy client interacts with the backend database server. The traditional multi-tier architecture includes the following components: 1. Start the client or server process (start operation); 2. the application server performs some operations. The Application Server contains most of the application logic and provides the client with access permissions and Query Processing for data. The application server acts as an interface between the client and the database server, and provides additional security levels. (Perform the operation) 3. the data used in the operation is stored on the database server (storage operation). operations performed by the Application Server are supported. verify the client (such as web) credential 2. connect to the Oracle Database Server 3. represents the client to perform operations on Oracle database architecture Oracle database server architecture three main structures: memory structure, process structure and storage structure. A basic Oracle database system consists of an Oracle database and a database instance (memory and process ). A database consists of a physical structure and a logical structure. Because the physical and logical structures are separated, the physical storage of data is managed without affecting access to the logical storage structure. The instance contains the memory structure and background processes associated with the instance. Each time an instance is started, a shared memory area in the global system zone (SGA) is allocated and background processes are started. A process is defined as a "control thread" or "mechanism" in the operating system. It can run a series of steps. After the database instance is started, Oracle software associates the instance with a specific database. Note: Oracle Automatic Storage Management (ASM) uses instances as memory and processing components, but is not associated with specific databases.

 

Database Configuration-single instance: each database instance corresponds to a unique database-Cluster: Multiple instances share a database RAC (Real Applications Cluster) to connect to the database instance-Session: indicates the status of the current user logging on to the database instance. The time when the user connects to the user to disconnect or exit the database application. -Connect: the communication path between the user process and the Oracle database instance.