Typical Oracle interview questions

1. Are you familiar with databases SQL2005 and Oracle?

SQL2005 is a database product of Microsoft. It is an RDBMS database, which is generally used in some medium-sized databases and cannot be used across platforms.

ORACLE is a data product of ORACLE. It supports massive data storage, distributed heat distribution, multi-user, cross-platform, and data security integrity control. It is an ORDBMS and is generally used in large companies.

2. Can I design a database? How to Implement Database Import and Export updates using the POWERDISINE tool is generally enough to meet the third paradigm. Logical Import and Export of EXP and IMP Databases

3. How to show only duplicate data or not duplicate data

Show duplicate: select * from tablename group by id having count (*)> 1

Duplicate: select * from tablename group by id having count (*) = 1

4. What is database ing?

It is the process of maps the table and field of the database to the class name and attribute of the model layer.

5. What methods do you use to write paging data? Write a paging using SQL statements?

How do I use stored procedures to write pages?

Use TOP paging in SQLSERVER, use ROWNUM in ORACLE, or use TOP as the analysis function ROW_NUMBER:

Select top 20, n. * from tablename n minus select top 10, m. * from tablename m

Use analysis functions:

Select * from

(Select n. *, row_number () over (order by columnname) num from tablename n)

Where num> = 10 and num <= 20;

When using the process, you only need to use two parameters for the paging range. In ORACLE, to encapsulate the process in the package, you must use a dynamic cursor variable to return the dataset.

6. Left and Right connections in ORACLE

Left join: left join right join: RIGHT JOIN

Select n. column, m. column from tablename1 n left join tablename2 m

On n. columnname = m. columnname

Implement with WHERE:

Select n. column, m. column from tablename1 n, tablename2 m

Where n. columnname () = m. columnname

7. What are reflection, serialization, and deserialization? What are the transaction levels?

Reflection is a way to dynamically access DDL when the program is running. Serialization stores objects directly to files in binary, XML, and other ways. Deserialization is the process of extracting objects stored in files. There are three transaction levels: Page Level, application level, and database level.

8. How to test data testing?

In PLSQL, the process or function may pass through a dedicated test tool

1 2 Next Page