How to log in to oracle database
Oracle database login involves not only username and password, but also connection strings (including server information and credentials) and authentication methods. It supports SQL*Plus and programming language connectors and provides authentication options such as username and password, Kerberos and LDAP. Common errors include connection string errors and invalid username/passwords, while best practices focus on connection pooling, parameterized queries, indexing, and security credential handling.
Oracle database login: It's not just username and password
You may think that logging into the Oracle database is simple, isn’t it just entering a username and password? In fact, this is not the case. There are many details hidden behind this, and even some safety hazards and performance issues that you may never notice. This article will take you into the deep understanding of Oracle database login mechanism, as well as some advanced techniques and potential pitfalls. After reading, you will have a deeper understanding of the connection methods, authentication, and security policies of Oracle databases, and write more robust and secure database applications.
Basics Review: Secrets of Connecting Strings
To connect to an Oracle database, you have to figure out the connection string first. It is like a key, opening the door to the database. A typical connection string contains this information:
- Database service name (ServiceName) or SID (System Identifier): This is the key to which database instance to connect to. ServiceName is more modern and recommended.
- Host name (Host) or IP address: the address of the database server.
- Port number (Port): The port of the database listener, the default is 1521.
- Username and Password: Your database account credentials.
An example connection string might look like this (Python example, similar to other languages):
<code class="python">connection_string = "oracle cx_Oracle://user:password@host:port/ServiceName"</code>
Here cx_Oracle is the Oracle database connector for Python. You have to install it: pip install cx_Oracle
Core concepts: connection method and authentication
Oracle database supports a variety of connection methods, such as the commonly used SQL*Plus command line tool, or database connectors for various programming languages. Authentication methods are also varied, including simple username and password verification, as well as more secure Kerberos or LDAP authentication.
Let's take a closer look at the details of username and password verification. Passwords are not stored directly in the database, but are stored after processing by a one-way hash function. This means that even if the database is compromised, the user's clear text password cannot be directly obtained. But this also means that once the password is lost, it cannot be retrieved and can only be reset.
Example of usage: SQL*Plus connects to Python
Logging in with SQL*Plus is very simple:
<code class="sql">SQL> connect user/password@ServiceName</code>
Connect with Python:
<code class="python">import cx_Oracle connection = cx_Oracle.connect(user='user', password='password', dsn='host:port/ServiceName') cursor = connection.cursor() cursor.execute("SELECT * FROM my_table") results = cursor.fetchall() # ... 处理结果... cursor.close() connection.close()</code>Note: This code only shows the most basic connection and query operations. It needs to handle exceptions in actual applications, such as connection failures, query errors, etc. Moreover, hard-code usernames and passwords directly in the code are very dangerous and a safer configuration method should be used, such as environment variables or configuration files.
Common Errors and Debugging Tips
- ORA-12154: TNS: could not resolve the connect identifier specified: This is usually a connection string error, checking whether the host name, port number and service name are correct.
- ORA-01017: invalid username/password; logon denied: Incorrect username or password.
- Connection timeout: Check the network connection and whether the database server is overloaded.
Performance optimization and best practices
- Connection pooling: Avoid frequent creation and closing of database connections, using connection pooling can significantly improve performance. Most database connectors provide connection pooling capabilities.
- Parameterized query: Avoid SQL injection and improve query efficiency.
- Index: Create indexes for frequently queried columns to speed up querying.
- Code optimization: Avoid unnecessary database operations and optimize SQL query statements.
Remember, database security is crucial. Never expose database credentials directly in your code, use a more secure authentication mechanism, and update your passwords regularly. A deep understanding of Oracle database login mechanism will help you write safer and more efficient database applications.
The above is the detailed content of How to log in to oracle database. For more information, please follow other related articles on the PHP Chinese website!
Hot AI Tools
Undresser.AI Undress
AI-powered app for creating realistic nude photos
AI Clothes Remover
Online AI tool for removing clothes from photos.
Undress AI Tool
Undress images for free
Clothoff.io
AI clothes remover
AI Hentai Generator
Generate AI Hentai for free.
Hot Article
Hot Tools
Notepad++7.3.1
Easy-to-use and free code editor
SublimeText3 Chinese version
Chinese version, very easy to use
Zend Studio 13.0.1
Powerful PHP integrated development environment
Dreamweaver CS6
Visual web development tools
SublimeText3 Mac version
God-level code editing software (SublimeText3)
Hot Topics
1378
52
Detailed explanation of docker principle
Apr 14, 2025 pm 11:57 PM
Docker uses Linux kernel features to provide an efficient and isolated application running environment. Its working principle is as follows: 1. The mirror is used as a read-only template, which contains everything you need to run the application; 2. The Union File System (UnionFS) stacks multiple file systems, only storing the differences, saving space and speeding up; 3. The daemon manages the mirrors and containers, and the client uses them for interaction; 4. Namespaces and cgroups implement container isolation and resource limitations; 5. Multiple network modes support container interconnection. Only by understanding these core concepts can you better utilize Docker.
How is the GPU support for PyTorch on CentOS
Apr 14, 2025 pm 06:48 PM
Enable PyTorch GPU acceleration on CentOS system requires the installation of CUDA, cuDNN and GPU versions of PyTorch. The following steps will guide you through the process: CUDA and cuDNN installation determine CUDA version compatibility: Use the nvidia-smi command to view the CUDA version supported by your NVIDIA graphics card. For example, your MX450 graphics card may support CUDA11.1 or higher. Download and install CUDAToolkit: Visit the official website of NVIDIACUDAToolkit and download and install the corresponding version according to the highest CUDA version supported by your graphics card. Install cuDNN library:
PHP and Python: Code Examples and Comparison
Apr 15, 2025 am 12:07 AM
PHP and Python have their own advantages and disadvantages, and the choice depends on project needs and personal preferences. 1.PHP is suitable for rapid development and maintenance of large-scale web applications. 2. Python dominates the field of data science and machine learning.
How to check CentOS HDFS configuration
Apr 14, 2025 pm 07:21 PM
Complete Guide to Checking HDFS Configuration in CentOS Systems This article will guide you how to effectively check the configuration and running status of HDFS on CentOS systems. The following steps will help you fully understand the setup and operation of HDFS. Verify Hadoop environment variable: First, make sure the Hadoop environment variable is set correctly. In the terminal, execute the following command to verify that Hadoop is installed and configured correctly: hadoopversion Check HDFS configuration file: The core configuration file of HDFS is located in the /etc/hadoop/conf/ directory, where core-site.xml and hdfs-site.xml are crucial. use
Python vs. JavaScript: Community, Libraries, and Resources
Apr 15, 2025 am 12:16 AM
Python and JavaScript have their own advantages and disadvantages in terms of community, libraries and resources. 1) The Python community is friendly and suitable for beginners, but the front-end development resources are not as rich as JavaScript. 2) Python is powerful in data science and machine learning libraries, while JavaScript is better in front-end development libraries and frameworks. 3) Both have rich learning resources, but Python is suitable for starting with official documents, while JavaScript is better with MDNWebDocs. The choice should be based on project needs and personal interests.
What are the backup methods for GitLab on CentOS
Apr 14, 2025 pm 05:33 PM
Backup and Recovery Policy of GitLab under CentOS System In order to ensure data security and recoverability, GitLab on CentOS provides a variety of backup methods. This article will introduce several common backup methods, configuration parameters and recovery processes in detail to help you establish a complete GitLab backup and recovery strategy. 1. Manual backup Use the gitlab-rakegitlab:backup:create command to execute manual backup. This command backs up key information such as GitLab repository, database, users, user groups, keys, and permissions. The default backup file is stored in the /var/opt/gitlab/backups directory. You can modify /etc/gitlab
What to do after centos stops maintenance
Apr 14, 2025 pm 08:48 PM
After CentOS is stopped, users can take the following measures to deal with it: Select a compatible distribution: such as AlmaLinux, Rocky Linux, and CentOS Stream. Migrate to commercial distributions: such as Red Hat Enterprise Linux, Oracle Linux. Upgrade to CentOS 9 Stream: Rolling distribution, providing the latest technology. Select other Linux distributions: such as Ubuntu, Debian. Evaluate other options such as containers, virtual machines, or cloud platforms.
What steps are required to configure CentOS in HDFS
Apr 14, 2025 pm 06:42 PM
Building a Hadoop Distributed File System (HDFS) on a CentOS system requires multiple steps. This article provides a brief configuration guide. 1. Prepare to install JDK in the early stage: Install JavaDevelopmentKit (JDK) on all nodes, and the version must be compatible with Hadoop. The installation package can be downloaded from the Oracle official website. Environment variable configuration: Edit /etc/profile file, set Java and Hadoop environment variables, so that the system can find the installation path of JDK and Hadoop. 2. Security configuration: SSH password-free login to generate SSH key: Use the ssh-keygen command on each node
