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Introduction The Java 8 API adds a new abstraction called streaming Stream, which allows you to process data in a declarative way. Stream provides a high-level abstraction of Java set operations and expressions in an intuitive way similar to querying data from a database using SQL statements. Stream API can greatly improve the productivity of ...

An insert operation Take the simple operation of saving a record to the table as an example. Follow this example to track how the MySQL statement executes. To save a user record to the table: sqlSession.insert("x.y.insertUser", user); First of all, we need to look at the sqlsession ා insert method, and find the specific implementation in the D ...

Relational query Exchange rate table data db.forex.insert([ { ccy: "USD", rate: 6.91, date: new Date("2018-12-21") }, { ccy: "GBP", rate: 8.72, date: new Date("2018-08-21") }, { ccy: "CNY", rate: 1.0, date: new Date("2018-10-21") } ]) User table dat ...

In order to study whether sql automatic inspection and analysis tools are easy to use, I install and use soar and soar web locally. The preliminary experimental results are summarized as follows: 1. The installation is relatively cumbersome, especially the installation of dependency package of soar web, which involves the download and installat ...

Original link: http://www.yiidian.com/hibernate/hibernate-get-load.html 1. Demonstrate the basic use of get and load methods /** * Show basic object query * @author http://www.yiidian.com * */ public class Demo { /** * get()Method: query an object */ @Test public void test1(){ Session session = HibernateUtil.getSession(); Transa ...

Preface wcdb has been in the pit for two months, which is still very good on the whole. For specific advantages, please refer to the documentation. Because the official specification does not support SQL, we have to write an extension to support it A kind of   statement Welcome to reprint, but please keep the original source of the article:) ...

Session information function (2) Current "catalog and current" database () both return the name of the currently connected database. testdb=# select current_database(); current_database ------------------ testdb (1 Row record) testdb=# select current_catalog; current_database ------------------ testd ...

Author: Lao Wang Tan operation and maintenancehttps://www.toutiao.com/a6691523026984370699/ What is the performance of mysql running? Is the parameter setting reasonable? Is there any hidden danger in the account setting? As the saying goes, if you want to be good at something, you must first make use of the device. Regular physical examinati ...

This article records the characteristics of the first level cache in Hibernate. Details of L1 cache: what operations will be directed to 1. Level cache put data save,update,saveOrUpdate,load,get,list,iterate,lock 2. What operation will fetch data from the first level cache.get / load / list get / load will first get from the first level cache. ...

1, Environment introduction System platform: CentOS release 6.6 (Final) Postgresql: postgresql-9.6.6 SELINUX=disabled Iptables off 2, Installation process 1. Install dependency package yum -y install gcc* yum -y install readline-devel 2. Source package acquisition wget http://ftp.postgresql.org/pub/source/v9.6. ...