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Introduction: Oracle Database, also known as Oracle RDBMS, or Oracle for short. It is a relational database management system of Oracle. It is a leading product in the field of database. It can be said that Oracle database system is a popular relational database management system in the world at present. The system has good portability, easy to use and strong function, and is suitable for all kinds of large, medium, small and microcomputer environments. It is a database solution with high efficiency and good reliability, which adapts to high throughput. Oracle Database 12C is an updated version of Oracle11g. Overview: this article introduces the basics of Oracle12c, as well as the basics of Oracle12c installer and database configuration assistant (Database Configuration Assistant,DBCA) installation of Oracle12c. You will also introduce the various elements that make up the Oracle12C instance, including memory structure, disk structure, initial parameters, tables, indexes, and PL/SQL. Database and instance: * although the terms "database" and "instance" are often used interchangeably, there is a big difference between them. In the Oracle data center, they are completely different entities. * A database is a collection of data on disk, located in one or more files on the database server that collects and maintains relevant information. The database consists of a variety of physical and logical structures, and the table is the most important logical structure in the database. The table consists of related rows and columns that contain data. * the files that make up the database are mainly divided into two categories: database files and non-database files. The difference between the two is what kind of data is stored. Database files contain data and metadata, while non-database files contain initial parameters and logging information. Database files are essential for ongoing database operations all the time. * the main components of a typical enterprise server are one or more CPU (with multiple cores), disk space and memory. The Oracle database is stored on the disk of the server, while the Oracle instance exists in the memory of the server. The Oracle instance consists of a large block of memory and a large number of background processes; the memory block is allocated in the global area of the system, and the background processes interact between SGA and database files on disk. * in OracleRAC, multiple instances will use the same database. While instances of shared databases may be on the same server, it is most likely that these instances are on different servers that connect through high-speed interconnects and access databases that reside on dedicated, RAID-enabled disk subsystems. The Oracle Exadata database all-in-one machine is an example of combining database servers, Imax O servers, and disk storage into one or more cabinets and optimizing for RAC environments (including dual InfiniBand interfaces that connect all these devices at the speed of 40Gbps per interface). Oracle 12c database architecture

Installation environment: * installation system: CentOS 7 * IP address: 192.168.72.129 * hard disk size: 40g or remount a 40G hard disk * memory: 4G * SWAP (virtual memory): 8G * package link: https://pan.baidu.com/s/1XA6WUchSzhxH3qYevF0gxA * you can also go directly to the official website to download: https://www.oracle.com/cn

Installation process: 1. First deploy the environment, install the environment package, turn off the firewall and security * yum-y install binutils compat-libcapl compat-libstdc++-33 gcc gcc-c++ glibc glibc-devel ksh libaio libaio-devel libgcc libstdc++ libstdc++-devel libXi libXtst make sysstat unixODBC unixODBC-devel* systemctl stop firewalld.service* setenforce 0

two。 Hostname * vim / etc/hostname # add hostname HOSTNAME=oracle # add * vim / etc/hosts # resolve hostname 192.168.72.129 oracle # add 3. The recommended value for configuring the kernel parameter * vim / etc/sysctl.conf fs.aio-max-nr = 1048576 # number of asynchronous IO requests is: 1048576 is actually equal to 1024024, that is, the maximum number of file handles opened by 1024 fs.file-max = 6815744 #. The problem to prevent file descriptor exhaustion is kernel.shmall = 2097152 # total shared memory pages. Kernel.shmmax divided by 4k kernel.shmmax = 4294967295 # maximum memory kernel.shmmni = 4096 # minimum memory kernel.sem = 250 32000 100 128 # SEMMSL: maximum number of signals per semaphore set SEMMNS: maximum number of signals used to control the entire Linux system SEMOPM: kernel parameters are used to control the number of signal operations that can be performed per semop system call SEMMNI: kernel parameters are used to control Control the maximum number of signals in the entire Linux system net.ipv4.ip_local_port_range = 9000 65500 # Port range for outgoing connections net.core.rmem_default = 262144 # default value of socket receive buffer size net.core.rmem_max = 4194304 # maximum socket receive buffer size net.core.wmem_default = 262144 # socket send buffer size Default value net.core.wmem_max = 1048576 # maximum socket send buffer size * sysctl-p # to make it effective

User environment configuration 1. Create oracle user and password * groupadd oinstall* groupadd dba* useradd-g oinstall-G dba oracle* passwd oracle

two。 Create the oracle working directory * mkdir-p / orc/app/oracle* chown-R oracle.oinstall / orc/app/* chmod-R 755 / orc/app/oracle/3. Set the environment variable * vim / home/oracle/.bash_profile # first delete the last two rows of data to insert umask 022 # create file permissions ORACLE_BASE=/orc/app/oracle # installation path OPACLE_HOME=/orc/app/oracle/product/12.2.0/dbhome_1/ # specify installation product ORACLE_SID=orcl # instance NLS_LANG= "SIMPLIFIED CHINESE_CHINA" .UTF8 # language is simplified Chinese PATH=$PATH:$HOME/.local/bin:$HOME/bin:$ORACLE_HOME/bin # oracle command is imported into the environment variable LANG=zh_CN.UTF-8 # character set export PATH LANG NLS_LANG ORACLE_BASE ORACLE_HOME ORACLE_SID # declares the global Easy for system identification

Oracle user resource limit 1. Use the pam_limits authentication module * vim / etc/pam.d/login to add: session required / lib/security/pam_limits.so session required pam_limits.so under line 7

two。 Configuration limit file * vim / etc/security/limits.conf Last Line add: oracle soft nproc 2047 # processes available to a single user oracle hard nproc 16384 oracle soft nofile 1024 # number of files that users can open oracle hard nofile 65536 oracle soft stack 10240 # stack setting

3. Modify the environment variable * vim / etc/profile add: if [$USER = "oracle"] then if [$SHELL = "/ bin/ksh"] then ulimit-p 16384 # buffer size ulimit-n 65536 # number of files else ulimit-u 16384-n 65536 # number of processes fifi

Install Oracle

With all the installation prerequisites in place, start the Oracle installation now.

1.。 Mount the unzipped database package in Linux

two。 Next, operating xhost + # in the graphical interface requires the root identity to operate in the graphical interface 3. Switch Oracle user installation Oracle database su-oracle / / switch to oracle user export DISPLAY=:0.0 # you must have this step cd / aaa/Oracle package / database # switch to this directory. / runInstaller / / start installation waiting for pop-up window

4. Next, the desktop pops up a window of Oracle to install.

* switch root users to execute scripts: * / orc/app/oraInventory/orainstRoot.sh* / orc/app/oracle/product/12.2.0/dbhome_1/root.sh

5. After the installation is complete, use your browser to access https://192.168.72.129:5500/em

To this Oracle 12c installation is complete, the specific operation and internal storage is only detailed in the next article!

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