20165235 Qi Ying 2018-4 Java Programming Seventh Week study summary textbook learning content summary MySQL data management system
MySQL数据管理系统
, short MySQL
, is the world's popular data management system.
MySQL
is a network database management system that enables a remote computer to access the database it manages.
Windows
MySQL
after downloading, go to Windows
the command line, enter MySQL
the directory to enter the bin
file directory to --initialize-insecure
MySQL
data
initialize. You can then bin
re-enable it in the directory mysql
MySQL
. When enabled, you MySQL
cannot end a process by closing the command line, and you Windows
can use shortcut keys to end a process by using Task Manager on. shift+ctrl+Esc
- Can download the
Navicat
software, this is a good MySQL
client management tool (but to charge, I use the free version). Then follow the steps of the textbook to establish the link.
MySQL
The port is occupied 3360
. The host name can be written directly localhost
. (Take the MySQL
domain name or IP of the calculator where the server is located)
JDBC-MySQL
Drivers can make Java
connections between applications and MySQL
databases.
- Programs commonly used
JDBC
to do the following: 1. Establish a connection to a database. 2. Send the statement to the connected data path SQL
. 3. Process SQL
the returned results.
- Using a
JDBC-
database-driven approach to establishing a connection with a database requires the following steps: 1. Load the JDBC-
database driver. 2. Establish a connection to the specified database.
- Download the file on the MySQL official website
mysqld-connector-java-bin.jar
and copy it to the jdk1.8/jre/lib/ext
directory.
- Drive the JDBC code as follows:
try{ Class.forName("com.mysql.jdbc.Driver"); } catch(Exception e){}
To establish a connection after starting the JDBC driver, establish the connection code as follows:
connection con;String uri="jdbc:mysql://localhost:3306/students?useSSL=true";try{con= DriverManager.getConnection(uri,user,password);}catch(SQLException e){ }
If the user password is 123
available &password=改成&password=123
.
Query operations
- After establishing a connection with the database, you can use the API and database interaction information provided by JDBC, query, modify and so on.
Sending SQL statements to the database
try {statement sql =con.ctrateStatement();}catch(SQLException e){}
With the SQL object, you can invoke the appropriate method to implement the query operation of the data and store the query operations in the ResultSet
object declared by the class. For example, the following code:
ResultSet rs = sql.executeQuery("SELECT*FROM student"),//此处我建立的数据库名为student
As the textbook Code query is the mess table:
rs=sql.executeQuery("SELECT * FROM mess");
One final step is to close the connection ascon.close()
Textbook Example11_1 Code test Operations and:
- This time I was in the
Windows
dos
command line under the database operation, so downloaded MySQL
, the Navicat
software, but also downloaded the JDBC-
database driver mysqld-connector-java-bin.jar
and to put this .jar
file in the jdk1.8/jre/lib/ext
directory. After completing these, follow the tutorial in the textbook to initialize the MySQL
bin
file directory under, data
and enable MySQL
, this is enabled MySQL
:
- Establish a connection to the database and establish a
Navicat
database named, student
and create a mess
table, such as:
- Then open another
dos
command line, run the Example11_1.java
file, and run the result as follows:
Problems in teaching materials learning and the solving process
- In this operation encountered a lot of problems
- Issue one: In the run
MySQL
times the error is as follows:
- WORKAROUND: I downloaded to the file on the Internet
MSVCR120.dll
and then copied to the directory under the system directory SysWOW64
, the results are still error, and then search the Web to download the repair program to repair it, and finally succeeded. As follows:
Code hosting 1 Code hosting 2
Last week's five-week error summary of the wrong question summary:
- 6. Calling a linear
interrupt()
method throws: The CloseByInterruptException
exception object
- 8. Custom exception classes can be more specific to determine the location of the error of the bit and give detailed error information.
-
FileInputStream
class inherits from InputStream
the ability to read files in bytes.
ByteArrayOutputStream(int size)
the buffer default size is determined by size.
- A stream
BufferedWriter
can point to a FileWriter
stream.
java
use throw
the throws
declaration method to throw an exception using the throw exception.
45. For a serious error, it is described by a class Error
, and a very serious error is described by the Exception
class.
Summary of six-week wrong questions:
- 6. Throws an exception if the specified object cannot be compared with the
set
current element in the. ClassCastException
\b\w{6}\b
matches exactly 6 characters of a word.
new Data(System.currentTimeMillis())
equivalence andnew Date()
Sentiment
This time learning MySQL feel learned a lot of things, the database also has a lot of understanding. In the operation of the time will inevitably encounter some mistakes, it is important to try to solve, instead of relying on classmates, teachers (really can not solve is to teachers, students seeking help). And in the study of the database will use some SQL statements, learning SQL statements for the master MySQL database operation is also an important method. Because the last time did not finish the eighth chapter of the code, this time I fill in the code, the link to the code.
Learning progress Bar
|
lines of code (new/cumulative) |
Blog Volume (Add/accumulate) |
Learning Time (new/cumulative) |
Important Growth |
Goal |
5000 rows |
30 Articles |
400 hours |
|
First week |
31/31 |
1/1 |
20/20 |
The use of Git |
Second week |
373/404 |
2/3 |
18/38 |
Java Basic Data syntax |
Third week |
547/920 |
1/4 |
22/60 |
Classes and objects and packaging |
Week Four |
919/1839 |
2/6 |
30/80 |
Subclass and inheritance, interface and interface-oriented programming |
Week Five |
500/2300 |
3/9 |
20/100 |
Input and output streams and internal classes |
Week Six |
300/2600 |
1/10 |
25/125 |
Generic and aggregate frameworks, common utility classes |
Seventh Week |
447/3047 |
3/13 |
25/150 |
MySQL database and JDBC |
Resources
20165235 Qi Ying 2018-4 "Java Programming" Seventh Week study summary