JDBC [1] - primary addition, deletion, modification and query
[TOC]
1. What is JDBC
JDBC (Java database connectivity) is a Java API for executing SQL statements. It can provide unified access to a variety of relational databases. It is composed of a group of classes and interfaces written in Java language. JDBC provides a benchmark by which more advanced tools and interfaces can be built to enable databa ...
Posted by arth on Thu, 05 May 2022 08:55:55 +0300
The mysql GTID master-slave replication fails and the synchronization process is resumed without stopping
GTID realizes master-slave replication data synchronization
GTID is a successfully executed global transaction ID generated based on the original mysql server. It consists of server ID and transaction ID. this global transaction ID is unique not only on the original server, but also on all mysql servers with master-slave relationship. Officiall ...
Posted by dharprog on Thu, 05 May 2022 06:29:39 +0300
hadoop+hive notes on deploying stand-alone version
preface
For the deployment test conducted on the Ubuntu 18 version of the native simulator, refer to the official document:
hadoop: Link address
hive: Link address
Version used:
hadoop: 3.2.1
hive: 3.1.2
The whole process is configured with the root account.
hadoop installation configuration
hadoop uses a virtual cluster, that is, a singl ...
Posted by anshu.sah on Thu, 05 May 2022 05:22:18 +0300
Database Experiment - Triggers and Database Security
📧 Triggers and database security Tip: The general content of this article: This experiment is from topics 7 to 10 of "Database Principles and Technologies" of Tsinghua University Press. 2. P396 on-line experimental questions 8. 3. P396 computer experiment questions 9 topics.
Preface
😁 Again, the old saying goes: the basic pr ...
Posted by qazwsx on Wed, 04 May 2022 20:06:17 +0300
Record the formulation and implementation of an online Mysql database migration plan
foreword
The system has been in operation for many years. The database server has also been running for many years, and its performance is relatively old. The capacity of the SSD hard disk is only 250G. Under various demands, the disk of the current server is about to be insufficient. Therefore, the migration of this database was started.
nee ...
Posted by Myke on Wed, 04 May 2022 14:57:37 +0300
JDBC Programming: Advanced JDBC Programming
transaction processing
Bulk update
Returns the automatic primary key
DAO
1. Transaction processing
What are things?
Transaction: The mechanism in the database to ensure the reliability of transactions. JDBC supports the concept of transactions in the database, and in JDBC, transactions are automatically committed by default.
There are two wa ...
Posted by pabs1983 on Wed, 04 May 2022 12:30:43 +0300
Database Experiment 6 stored procedure
Database and table building
view the database
sentence
show datebases;
-- View all databases
effect
[take mine as an example, the following are]
mysql> show databases; ±-------------------+ | Database | ±-------------------+ | information_schema | | mysql | | performance_schema | | sqlfortextbook | | studb | | sys | ±------------- ...
Posted by izzy on Wed, 04 May 2022 09:52:20 +0300
May 3, 2022 [crazy God talking about Java] the latest tutorial of MySQL is easy to understand 2
2. Operation database
2.1 operation database
2.2 column type of database
numerical value
tinyint very small data 1 bytesmallint smaller data 2 bytesmediumint medium size 3 bytesint standard integer 4 bytesbigint larger datafloat floating point number 4 bytesdouble floating point number 8 bytesFinancial calculation of floating point num ...
Posted by grumpy on Tue, 03 May 2022 19:40:00 +0300
[MySQL notes] multi table query
Multi table query, also known as association query, refers to two or more tables completing the query operation together
catalogue
Prerequisites for multi table query
Basic syntax of multi table query
Classification of multi table query
Equivalent connection and non equivalent connection
Self connected and non self connected
Internal con ...
Posted by tanita on Tue, 03 May 2022 11:50:59 +0300
JDBC connection database
1, What is JDBC
When it comes to JDBC, we should first think of the 13 specifications in Java. One of them is JDBC. What is it and what is its use?
Let's take a look at Baidu Encyclopedia first
In short, it is the method of connecting the database with Java, but we all know that the Java language is developed and maintained by Oracle company, ...
Posted by tito on Mon, 02 May 2022 11:21:35 +0300