[JDBC] classic interview questions of JDBC, constantly updating

What is? JDBC？

JDBC The full name is Java DataBase Connection.
That is to say Java Get database connection , By using JDBC Related interfaces and classes . We can use it to connect to the database , perform SQL Statements, etc. .

What is? JDBC Connect ？ How to get the database /JDBC Connect ？

JDBC A connection is a session established between the host and the database server .
obtain JDBC Linking is mainly divided into two steps ：
1. Register and load the driver . call Class.forName（） Method . The driver class will be registered to DriverManager Class , And load it into memory .
2. call DriverManager Class getConnection Method . Incoming database connection url, user name , password , You can get the connection object .

JDBC How to achieve Java Procedure and JDBC Driven loosely coupled ？

There is only one case , Will be involved JDBC drive , Is the use Class.forName Reflection mechanism to register and load drivers .
All other operations are Java Program call JDBC Interface to complete . In this way Applications and The driver Isolation , If you want to change the database, it becomes simple .

JDBC Steps to connect to the database ？ Operate on data ？

1. Register and load the driver .
2. Use DriverManager Get the connection .
3. precompile sql sentence , return PreparedStatement.
4. Fill in placeholders .
5. Perform database operations .
6. Processing result set ResultSet.
7. close resource .