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2.2 Data Types
This chapter provides detailed descriptions of the differences in data types used by Microsoft SQL Server and Oracle databases. Specifically, this chapter contains the following information:
A table showing the base Microsoft SQL Server data types available and how they are map ...
Overview
Usually, the proxy class is already available as Java bytecodes, having been compiled from the Java source file for the proxy class.When needed, the bytecodes for the proxy class are loaded into the Java Virtual Machine and proxy objects can then be instantiated.But, in some circumst ...
Oracle SQL Developer offers the ability to create reports with graphs in it. A number of reports are included with the tool, unfortunately a report which shows information based on DBMS_PROFILER built in package isn’t there. DBMS_PROFILER allows developers to profile the run-time behaviour of PL/SQ ...
By Amar Kumar Padhi
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An application can always be fine-tuned for better performance with the use of better alternatives or with the new features introduced with every release of Oracle.
Simply inspecting the code can bring out the bottlenecks eating up your processing t ...
left join(左联接) 返回包括左表中的所有记录和右表中联结字段相等的记录 right join(右联接) 返回包括右表中的所有记录和左表中联结字段相等的记录inner join(等值连接) 只返回两个表中联结字段相等的行
举例如下： --------------------------------------------表A记录如下：aID aNum1 a200501112 a200501123 a200501134 a200501145 a20050115
表B记录如下:bID bName1 20060324012 ...
This topic illustrates the best practices to improve performance in JDBC with the following sections:
Overview of JDBC
Choosing the right Driver
Optimization with Connection
Set optimal row pre-fetch value
Use Connection pool
Control transaction
Choose optimal isolat ...
1.To get the table space usage in oracle use this query: SELECT a.tablespace_name, ROUND(a.bytes / 1024000) 'Used (MB)', ROUND(b.bytes / 1024000) 'Free (MB)', ROUND(((a.bytes -b.bytes) / a.bytes) *100, 2) '% USED' FROM (SELECT tablespace_name, SUM(bytes) bytes FROM dba_data_files ...
Oracle Locking Survival Guide
Overview
In multi-user systems, many users may update the same information at the same time. Locking allows only one user to update a particular data block; another person cannot modify the same data.
The basic idea of locking is that when a user modifies da ...