PL/SQL basic (variable, conditional statement, cursor)

brief introduction PL/SQL(Procedure Language/SQL) is a procedural extension of Oracle to SQL language. In SQL command language, process processing statements (such as branches, loops, etc.) are added to enable SQL language to process. So PL/SQL is a process oriented language. For other databases, ther ...

Posted on Mon, 17 Feb 2020 00:31:56 -0500 by Joe Haley

Regular tasks of ordinary users in linux

Reference resources: Details of crontab command Mail usage (use mail to view the execution of scheduled tasks) centos system forbids normal users to use crontab command Regular user-defined crontab scheduled tasks: For example, oracle user defines a timing task: print the current directory every minute [oracle@node2 ~]$ crontab ...

Posted on Thu, 13 Feb 2020 15:03:39 -0500 by f1nutter

How to learn the JVM gracefully

1, Understanding Java virtual machine stack and stack frame 1.1 what is stack frame? Each stack frame is considered to correspond to a called method, which can be understood as the running space of a method. Official address: https://docs.oracle.com/javase/specs/jvms/se8/html/jvms-2.html#jvms-2.6 Components of stack frame: 1. Local Variables: t ...

Posted on Mon, 10 Feb 2020 10:16:33 -0500 by serbestgezer

Technology sharing and quick handling of MySQL duplicate data

Author: Yang Taotao It's just that I'm helping customers migrate from the database of daydream to MySQL recently. Let me also briefly talk about the processing of duplicate data. There are three types of data stored in the database: One is data filtered by strict meaning. For example, the program side filters the data source, the database si ...

Posted on Mon, 10 Feb 2020 02:41:41 -0500 by dlkinsey85

MyBatis - dynamic SQL

MyBatis dynamic SQL (as learning notes, please refer to: MyBatis reference) if <select id="findActiveBlogLike" resultType="Blog"> SELECT * FROM BLOG WHERE state = 'ACTIVE' <if test="title != null"> AND title like #{title} </if> <if test="author != null and author.name != null"> ...

Posted on Sat, 08 Feb 2020 10:15:46 -0500 by phpstuck

Java Security: illegal key size or default parameter?

I asked a question earlier, but it didn't help that I didn't get the right answer. So I clarified some details about the problem, and I really want to hear from you about how to solve the problem or what you should try. I installed Java 1.6.0.12 on the Linux server, and the following code runs perfectly. String key = "av45k1pfb024xa3bl ...

Posted on Sat, 08 Feb 2020 08:59:42 -0500 by IronCannibal

User rights management of Oracle

User rights management of Oracle 1, Oracle user management Oracle user refers to the user who can add, delete, modify, and query the database. It mainly includes: Super administrator, such as SYS; general administrator, such as SYSTEM; general user, such as SCOTT; big data user. The operations that ...

Posted on Fri, 07 Feb 2020 03:43:32 -0500 by nishanthc12

Important points and examples of select function and group multi table connection in Oracle

Key points of select function and group multi table connection in Oracle function Function – built in and custom functions - single line function: a record returns a result of – multiline function | group function | aggregate function: multiple records return one result Single-Row Func ...

Posted on Wed, 05 Feb 2020 08:16:24 -0500 by Cronikeys

50 Linux Basic Operations Commands Must Be Mastered

Explain: Based on the author's usage in peacetime and some other reference materials, the following 50 basic Linux commands that must be mastered are carefully sorted out. Command: 1. ssh Log on to remote host $ ssh -l jsmith remotehost.example.com Debugging ssh client $ ssh -v -l jsmith remotehost.example.com Show ssh client version $ ssh ...

Posted on Mon, 03 Feb 2020 11:43:59 -0500 by mgason

Java collection source code analysis of LinkedList based on JDK 1.8

In the last part, we analyzed the underlying implementation of ArrayList, and learned that the underlying implementation of ArrayList is based on arrays, so it has the characteristics of fast search and modification, and slow insertion and deletion. LinkedList introduced in this paper is another implementation of List interface. Its bottom laye ...

Posted on Sun, 02 Feb 2020 06:42:09 -0500 by scuff