1. Hibernate is a JDO tool. Its working principle is the adoption of a document (usually there are two types: xml files and properties files) to the value of objects and database tables to establish a mapping between the relations. In this way, we only need to operate these values through the Hibernate objects and to provide some basic categories, you can achieve the purpose of the use of the database. For example, the use of Hibernate's query, can return a value object that contains a list (List), rather than the traditional JDBC to access the same data from the result set to a value loaded by the target, in order to encode a large number of job-saving时间. Hibernate provides the HQL is a type of SQL language, as it is to provide EJBQL object-oriented database query, but the functions and the use of HQL at the way standards are very close to SQL.
2. Hibernate and JDBC differences between Hibernate and JDBC main differences are as follows:
1. Hibernate are the subject of lightweight JDBC package, it is an independent object persistence framework, and the App Server, and EJB Nothing contact inevitable. Hibernate can use JDBC can be used in any occasion, from a certain sense, Hibernate in any occasions to replace the JDBC.
2. Hibernate and JDBC are closely related to a framework, so Hibernate and JDBC driver compatibility, and databases must have a relationship, but Java and the use of its procedures, and there is no relationship between the App Server does not exist compatibility problems .
3. Hibernate is used as a substitute for the emergence of JDBC, and can not be used to make a direct comparison and Entity Bean.
3. Hibernate multi-table related query Hibernate query to multiple tables, the query results are a number of the Cartesian product form, or referred to as the "cross" connection. For example: from Student, Book from Student as stu, Book as boo from Student stu, Book boo Note: Student let the query and the Book of all student and book form are the corresponding class name, it must be the first name and first name in the same category , including the upper and lower case letters. Alias lowercase the first letter should be subject to the rules is a good habit, which Java local variables on the naming convention is consistent.
2. Hibernate and JDBC differences between Hibernate and JDBC main differences are as follows:
1. Hibernate are the subject of lightweight JDBC package, it is an independent object persistence framework, and the App Server, and EJB Nothing contact inevitable. Hibernate can use JDBC can be used in any occasion, from a certain sense, Hibernate in any occasions to replace the JDBC.
2. Hibernate and JDBC are closely related to a framework, so Hibernate and JDBC driver compatibility, and databases must have a relationship, but Java and the use of its procedures, and there is no relationship between the App Server does not exist compatibility problems .
3. Hibernate is used as a substitute for the emergence of JDBC, and can not be used to make a direct comparison and Entity Bean.
3. Hibernate multi-table related query Hibernate query to multiple tables, the query results are a number of the Cartesian product form, or referred to as the "cross" connection. For example: from Student, Book from Student as stu, Book as boo from Student stu, Book boo Note: Student let the query and the Book of all student and book form are the corresponding class name, it must be the first name and first name in the same category , including the upper and lower case letters. Alias lowercase the first letter should be subject to the rules is a good habit, which Java local variables on the naming convention is consistent.