1) . configure data source related properties (see Druid in the previous section)
2) . creating tables for data ...
Posted by Mhz2020 on Sun, 05 Apr 2020 03:41:40 -0700
I often use SQL in my work, which has annoying subtle differences and limitations, but after all, it is the cornerstone of the data industry.Therefore, SQL is indispensable to every data worker.Being proficient in SQL means a lot.
SQL is good, but how can you just be satisfied with "good"?Why not proceed further with SQL?
Statements c ...
Posted by barnbuster on Sun, 05 Apr 2020 03:05:57 -0700
Business description: table A is the detailed statement of table B. now it is required that table B has millions of records. Insert the relevant records of table B in table A.
Preparation: oracle database, database tool pl\sql, stored procedures written in the package.
3.1 get the total data volu ...
Posted by name1090 on Sat, 04 Apr 2020 13:06:07 -0700
In fact, it is not difficult to configure spring boot jap+mybatis druid with multiple data sources
The key cannot be confused. Otherwise, after the configuration is completed, the connection of the druid data source may explode some strange errors, such as connection timeout, connection unavailable, etc
Create a DataSour ...
Posted by marcusb on Sat, 04 Apr 2020 04:01:17 -0700
In the previous article, I briefly introduced Linq's entry-level usage. This article tries to explain some more in-depth usage methods. Unlike the previous article, I will first introduce the support methods in Linq, and then write them in the form of method chain and SQL like, guided by the actual requirements.
Introduction to pre conc ...
Posted by rjs34 on Sat, 04 Apr 2020 02:58:21 -0700
(any SQL not explicitly indicated in this article is executed on the coordination node.)
mydb1=# SELECT * FROM master_get_active_worker_nodes();
node_name | node_port
192.168.7.131 | 5432
192.168.7.135 | 5432
192.168.7.136 | 5432
192.168.7.137 | 5432
Posted by loquela on Sat, 04 Apr 2020 00:20:48 -0700
JDBC(Java Database connectivity) is a Java API for executing SQL statements
Can provide unified access to a variety of relational databases
Java database connection specification (a set of interfaces)
There are four core classes of JDBC:
DriverManager create connection
Connection connection class
Posted by skaforey on Fri, 03 Apr 2020 13:54:08 -0700
Spring provides a powerful template class -- JDBC template to simplify JDBC operations. The data source DataSource object and the template JDBC template object can be defined in the configuration file in the form of Bean, giving full play to the power of dependency injection.
Case: use JDBC template to query all books
1. Introduce jar package ...
Posted by Loafin on Fri, 03 Apr 2020 01:06:22 -0700
1. Create user table
CREATE TABLE user100w(
id INT NOT NULL AUTO_INCREMENT,
first_name VARCHAR(10) NOT NULL,
last_name VARCHAR(10) NOT NULL,
sex VARCHAR(5) NOT NULL,
score INT NOT NULL,
copy_id INT NOT NULL,
PRIMARY KEY (`id`)
2. Create stored procedure
DROP PROCEDURE IF EXISTS add_user;
DELIMITER / ...
Posted by tensionx on Thu, 02 Apr 2020 21:24:46 -0700
Guide: is it very interesting to be able to carry out a single line or lines of SQL files? Today, let's introduce this interesting Library -- dotsql.
dotsql is not an ORM or a builder of SQL query statements, but a tool that can carry out several lines in an SQL file, very similar to the reading of ini configuration fi ...
Posted by ~n[EO]n~ on Thu, 02 Apr 2020 19:14:54 -0700