Operating code for database part knowledge using Java

This week, the first temporary end of Java advanced knowledge, into the database learning:

Java Advanced section:
1. Multithreading: Thread concurrency (multiple thread operations share variables);
Lock mechanism, keywords have synchronize (concurrent thread safety, lockable objects and methods), wait,notify
(pessimistic) deadlock, wait,notify,notifyall;
2. Network programming: UDP data Broadcast (data sender only need to send a copy to the switch, the switch is responsible for this information to make n copies sent to all machines)
HTTP protocol (hypertext Transfer Protocol)
JSON data format, Syntax rules: JSON object {"Property name": "Property Value"}
JSON array ["Element 1", "Element 2" ...]
Json Plugin:-Json-lib
-Gson
-Jackson
-Fastjson-alibaba
；
Database section: (using mysql5.5 database, and Navicat graphical tools to manipulate it)
3. System and MySQL common commands
System commands (run as Administrator)

: #启动服务
net start MySQL

#停止服务
net stop MySQL


#进入mysql命令行
Mysql-uroot-p Password

#退出mysql命令行
Exit


#修改密码
mysqladmin-uroot-p123456 Password Password
#备份数据库实例 Mysqldump-uroot-proot mydb > D:/mydb.sql
#备份表 mysqldump-uroot-proot mydb tbuser > D:/tbuser.sql

MySQL Common commands

:--Show DB instance
show databases;

--Create a DB instance
Create DATABASE MyDB;

--Using a DB instance
User mydb;

--Show all database tables in the instance
Show tables;

SQL statements

Auto_increment: Set column increment, available for primary and non-null unique columns (NOT NULL unique)

Unsigned: Set unsigned columns (column values are not allowed to be negative)

Zerofill: Set 0 Fill column (the value is 0 before the length of the column data is defined)

4.SQL statement:
DDL (Database definition language: Used to build databases, database objects, and define their columns): Create, DESC (view table structure), ALTER, drop
DML (Database Manipulation language: additions and deletions): SELECT, INSERT, delete, update;
DCL (Database Control Language: control permissions) revork,grant;
5. (Integrity condition) constraint: 1. PRIMARY KEY constraint
2. FOREIGN KEY constraints
3. Not a NULL constraint
4. Unique constraints
5. Check the constraints (MySQL is not supported temporarily)

6. Data types, operators
7. Query (FOCUS): SELECT query column 1, query column 2,...
From target table

"WHERE Query Condition"

"GROUP By Column name"

"Having a query condition"

"ORDER by column name asc| DESC "

"LIMIT [offset row,] record line Count"

Single table query: Fuzzy query ("%", "_"), aggregate function
Multi-table query: Equivalent connection, outer connection
The use of MySQL functions.

Import java.io.serializable;/** * Work details class * @author Niuxuyuan */public class jobs implements serializable{/** * */private s          Tatic final Long Serialversionuid = 1l;private String id;  Idprivate String experience;        Working experience private String city;    Work place private String industry;      Industry private String Detail;     Job Details private String company;     Company Private String JobName; Jobs public jobs (string ID, string experience, String city, string industry, string detail, string company,string jobname) {super (); this.id = Id;this.experience = experience;this.city = City;this.industry = Industry;this.detail = detail; This.company = Company;this.jobname = JobName;} @Overridepublic String toString () {return "Jobs [id=" + ID + ", experience=" + Experience + ", city=" + City + ", industry = "+ industry+", detail= "+ Detail +", company= "+ company +", jobname= "+ JobName +"] ";} Public String toString (int i) {return experience+city+industry+detail+company+jobname;} Public Jobs () {//TODO auto-Generated constructor stub}public String getId () {return ID;} public void SetId (String id) {this.id = ID;} Public String getexperience () {return experience;} public void Setexperience (String experience) {this.experience = experience;} Public String getcity () {return city;} public void Setcity (String city) {this.city = city;} Public String Getindustry () {return industry;} public void Setindustry (String industry) {this.industry = industry;} Public String Getdetail () {return detail;} public void Setdetail (String detail) {this.detail = detail;} Public String Getcompany () {return company;} public void Setcompany (String company) {this.company = company;} Public String Getjobname () {return jobname;} public void Setjobname (String jobname) {this.jobname = JobName;}}

Import Java.io.bufferedreader;import Java.io.file;import Java.io.fileinputstream;import Java.io.filenotfoundexception;import Java.io.fileoutputstream;import Java.io.ioexception;import Java.io.inputstreamreader;import Java.io.objectinputstream;import Java.io.objectoutputstream;import Java.util.arraylist;import Java.util.list;public class Addjobs {static list<jobs> List = new arraylist<> (); File File = new file ("Jobs");/** * Input data * @throws ioexception */public void input () throws IOException {Bufferedreade     R br = new BufferedReader (new InputStreamReader (system.in));     System.out.println ("Fill in id/experience/education/city/industry/detail/company/jobname format:");     String msg = ""; while (!) (     msg = Br.readline ()). Equalsignorecase ("quit")) {Add (msg); } br.close ();} /** * Convert data into a jobs object into the list collection * @param msg */private void Add (String msg) {string[] s = msg.split ("/"); Jobs job = new jobs (S[0], s[1], s[2], s[3], s[4], s[5], s[6]); List.add (job);} private void Checkfile () tHrows FileNotFoundException, IOException, classnotfoundexception {if (File.length () >0) {ObjectInputStream ois = new ObjectInputStream (new FileInputStream (file)); list<jobs> temp = (list<jobs>) ois.readobject (); if (temp!=null) {list.clear (); for (Jobs t:temp) {List.add (t );}} Ois.close ();}}  public static void Main (string[] args) throws FileNotFoundException, IOException, classnotfoundexception {addjobs AJ = new Addjobs (); if (!aj.file.exists ()) {aj.file.createNewFile ();} Aj.checkfile (); Aj.input () ObjectOutputStream oos = new ObjectOutputStream (new FileOutputStream (Aj.file)); O Os.writeobject (list); Oos.close ();}}

Import Java.io.bufferedreader;import Java.io.file;import Java.io.fileinputstream;import Java.io.filenotfoundexception;import Java.io.ioexception;import Java.io.inputstreamreader;import Java.io.objectinputstream;import Java.util.arraylist;import Java.util.list;public class Query {static List<Jobs > list = new arraylist<> (); File File = new file ("Jobs");/** * View file, import data into List collection * @throws filenotfoundexception * @throws IOException * @throws Cl Assnotfoundexception */private void Checkfile () throws FileNotFoundException, IOException, classnotfoundexception {if ( File.length () >0) {ObjectInputStream ois = new ObjectInputStream (new FileInputStream (file)); list<jobs> temp = (list<jobs>) ois.readobject (); if (temp!=null) {list.clear (); for (Jobs t:temp) {List.add (t );}} Ois.close ();}} public void Check () throws IOException {BufferedReader br = new BufferedReader (new InputStreamReader (system.in)); System.out.println ("Please enter some letters of Experience/education/city/industry/detail/company/jobname"); String msg = Br.readline (); String[] s = msg.split ("/"); String regex = ""; for (string str:s) {regex + = "[\\s\\s]*" + str + "[\\s\\s]*";} list<jobs> temp = new arraylist<> (); for (Jobs j:list) {msg = j.tostring (1); if (Msg.matches (regex)) {Temp.add ( j);}} SYSTEM.OUT.PRINTLN ("result"); for (jobs jobs:temp) {System.out.println (jobs);}} public static void Main (string[] args) throws FileNotFoundException, ClassNotFoundException, ioexception {Query q = new Qu Ery (); Q.checkfile (); Q.check ();}}

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