Home Database Mysql Tutorial 经典Oracle面试题目

经典Oracle面试题目

Jun 07, 2016 pm 05:21 PM
oracle interview questions

经典Oracle面试题目

ORACLE是ORACLE公司的数据产品,支持海量数据存储,支持分布式布暑,支持多用户,跨平台,数据安全完整性控制性能优越,是一个OR

1、对数据库SQL2005、Oracle熟悉吗?

SQL2005是微软公司的数据库产品。是一个RDBMS数据库,一般应用在一些中型数据库的应用,不能跨平台。

ORACLE是ORACLE公司的数据产品,支持海量数据存储,支持分布式布暑,支持多用户,,跨平台,数据安全完整性控制性能优越,是一个ORDBMS,一般用在大型公司。

2、能不能设计数据库?如何实现数据库导入与导出的更新 使用POWERDISINE工具的使用,一般满足第三范式就可以了。EXP与IMP数据库的逻辑导入与导出

3、如何只显示重复数据,或不显示重复数据

显示重复:

select * from tablename group by id having count(*)>1
Copy after login

不显示重复:

select * from tablename group by id having count(*)=1
Copy after login

4、什么是数据库的映射

就是将数据库的表与字段对应到模型层类名与属性的过程

5、写分页有哪些方法,你一般用什么方法?用SQL语句写一个分页?

如何用存储过程写分页?

在SQLSERVER中使用TOP分页,在ORACLE中用ROWNUM,或分析函数ROW_NUMBER 使用TOP:
select top 20,n.* from tablename n minus select top 10,m.* from tablename m
Copy after login

使用分析函数:

select * from
(select n.*,row_number() over(order by columnname) num from tablename n)
where num>=10 and num <=20;
Copy after login

使用过程时,只要将分页的范围用两个参数就可以实现。在ORACLE中,要将过程封装在包里,还要用动态游标变量才能实现数据集的返回。

6、ORACLE中左连接与右连接

左连接:LEFT JOIN 右连接:RIGHT JOIN

select n.column,m.column from tablename1 n left join tablename2 m
on n.columnname=m.columnname
Copy after login

用WHERE实现:

select n.column,m.column from tablename1 n, tablename2 m
where n.columnname( )=m.columnname
Copy after login

7、什么是反射、序列化、反序列化?事务有几种级别?

反射是在程序运行时动态访问DDL的一种方式。序列化是将对象对二进制、XML等方式直接向文件的存储。反序列化是将存储到文件的对象取出的过程。事务的级别的三种:页面级、应用程序级、数据库级。

【专题推荐】:2020年oracle面试题汇总(最新)

Statement of this Website
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn

Hot AI Tools

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

Video Face Swap

Video Face Swap

Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Tools

Notepad++7.3.1

Notepad++7.3.1

Easy-to-use and free code editor

SublimeText3 Chinese version

SublimeText3 Chinese version

Chinese version, very easy to use

Zend Studio 13.0.1

Zend Studio 13.0.1

Powerful PHP integrated development environment

Dreamweaver CS6

Dreamweaver CS6

Visual web development tools

SublimeText3 Mac version

SublimeText3 Mac version

God-level code editing software (SublimeText3)

Hot Topics

Java Tutorial
1659
14
PHP Tutorial
1259
29
C# Tutorial
1233
24
When might a full table scan be faster than using an index in MySQL? When might a full table scan be faster than using an index in MySQL? Apr 09, 2025 am 12:05 AM

Full table scanning may be faster in MySQL than using indexes. Specific cases include: 1) the data volume is small; 2) when the query returns a large amount of data; 3) when the index column is not highly selective; 4) when the complex query. By analyzing query plans, optimizing indexes, avoiding over-index and regularly maintaining tables, you can make the best choices in practical applications.

Can I install mysql on Windows 7 Can I install mysql on Windows 7 Apr 08, 2025 pm 03:21 PM

Yes, MySQL can be installed on Windows 7, and although Microsoft has stopped supporting Windows 7, MySQL is still compatible with it. However, the following points should be noted during the installation process: Download the MySQL installer for Windows. Select the appropriate version of MySQL (community or enterprise). Select the appropriate installation directory and character set during the installation process. Set the root user password and keep it properly. Connect to the database for testing. Note the compatibility and security issues on Windows 7, and it is recommended to upgrade to a supported operating system.

MySQL: Simple Concepts for Easy Learning MySQL: Simple Concepts for Easy Learning Apr 10, 2025 am 09:29 AM

MySQL is an open source relational database management system. 1) Create database and tables: Use the CREATEDATABASE and CREATETABLE commands. 2) Basic operations: INSERT, UPDATE, DELETE and SELECT. 3) Advanced operations: JOIN, subquery and transaction processing. 4) Debugging skills: Check syntax, data type and permissions. 5) Optimization suggestions: Use indexes, avoid SELECT* and use transactions.

Can mysql and mariadb coexist Can mysql and mariadb coexist Apr 08, 2025 pm 02:27 PM

MySQL and MariaDB can coexist, but need to be configured with caution. The key is to allocate different port numbers and data directories to each database, and adjust parameters such as memory allocation and cache size. Connection pooling, application configuration, and version differences also need to be considered and need to be carefully tested and planned to avoid pitfalls. Running two databases simultaneously can cause performance problems in situations where resources are limited.

RDS MySQL integration with Redshift zero ETL RDS MySQL integration with Redshift zero ETL Apr 08, 2025 pm 07:06 PM

Data Integration Simplification: AmazonRDSMySQL and Redshift's zero ETL integration Efficient data integration is at the heart of a data-driven organization. Traditional ETL (extract, convert, load) processes are complex and time-consuming, especially when integrating databases (such as AmazonRDSMySQL) with data warehouses (such as Redshift). However, AWS provides zero ETL integration solutions that have completely changed this situation, providing a simplified, near-real-time solution for data migration from RDSMySQL to Redshift. This article will dive into RDSMySQL zero ETL integration with Redshift, explaining how it works and the advantages it brings to data engineers and developers.

Laravel Eloquent ORM in Bangla partial model search) Laravel Eloquent ORM in Bangla partial model search) Apr 08, 2025 pm 02:06 PM

LaravelEloquent Model Retrieval: Easily obtaining database data EloquentORM provides a concise and easy-to-understand way to operate the database. This article will introduce various Eloquent model search techniques in detail to help you obtain data from the database efficiently. 1. Get all records. Use the all() method to get all records in the database table: useApp\Models\Post;$posts=Post::all(); This will return a collection. You can access data using foreach loop or other collection methods: foreach($postsas$post){echo$post->

The relationship between mysql user and database The relationship between mysql user and database Apr 08, 2025 pm 07:15 PM

In MySQL database, the relationship between the user and the database is defined by permissions and tables. The user has a username and password to access the database. Permissions are granted through the GRANT command, while the table is created by the CREATE TABLE command. To establish a relationship between a user and a database, you need to create a database, create a user, and then grant permissions.

MySQL: The Ease of Data Management for Beginners MySQL: The Ease of Data Management for Beginners Apr 09, 2025 am 12:07 AM

MySQL is suitable for beginners because it is simple to install, powerful and easy to manage data. 1. Simple installation and configuration, suitable for a variety of operating systems. 2. Support basic operations such as creating databases and tables, inserting, querying, updating and deleting data. 3. Provide advanced functions such as JOIN operations and subqueries. 4. Performance can be improved through indexing, query optimization and table partitioning. 5. Support backup, recovery and security measures to ensure data security and consistency.

See all articles