It was in 2002, and MySQL 4.1 began to support UTF-8 coding RFC 2279 It is stipulated that the code uses 1 ~ 6 bytes to store a single character, and MySQL developers checked it in September of the same year Source code The UTF-8 encoding is changed from the maximum 6 bytes to 3 bytes, so there is the current UTF8MB3. As we all know, U ...
Posted on Tue, 07 Dec 2021 02:36:02 -0500 by misterguru
Using amoeba to separate mysql reading and writing
1. What is amoeba?
Amoeba (amoeba) project focuses on the development of distributed database proxy. Located between Client and DB Server(s). Transparent to clients. It has load balancing, high availability, sql filtering, separation of reading and writing, routing related queries to the targ ...
Posted on Mon, 06 Dec 2021 22:39:12 -0500 by ironmonk3y
JDBC (Java database connectivity)
Is a Java API for executing SQL statements, which 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, according to which more advanced tools and interfaces can be built, so that database develo ...
Posted on Mon, 06 Dec 2021 16:44:34 -0500 by mnewhart
The redis server uses port 6379 by default to communicate with the outside world, so we can actually implement a simple redis client on our own. This is done in java. Implementing a redis client consists of two main parts
socket communicationEncoding and decoding of redis communication protocol
The second part is mainly the implementation of ...
Posted on Mon, 06 Dec 2021 12:49:12 -0500 by goobers
Using fluent mybatis, you don't have to write specific xml files. You can construct more complex business sql statements through java api to achieve the integration of code logic and sql logic. You no longer need to assemble queries or update operations in Dao, or reassemble parameters in xml and mapper. Compared with native Mybatis, Mybatis Pl ...
Posted on Sun, 05 Dec 2021 20:51:29 -0500 by scialom
flyway is a database migration tool that supports automatic backup and execution of SQL scripts. It is very convenient for us to deploy applications to multiple environments to initialize databases or upgrade database tables.
1, Why use flyway
Let's make an analogy with the Git version control tool, which is often used now. It can well ...
This article describes how to install DBMS in local 19c and 21c databases_ Cloud package. The package is installed in the database on the Oracle cloud.
DBMS_CLOUD PackageOracle Cloud Infrastructure (OCI) : Create an Object Storage BucketOracle Cloud : Autonomous Database (ADW or ATP) - Load Data from an Object Store (DBMS ...
Posted on Sun, 05 Dec 2021 13:23:53 -0500 by slick101
Chapter 5 SQL predicate BETWEEN
scalar-expression BETWEEN lowval AND highval
Scalar expression - a scalar expression (most commonly a data column) that compares its value to the range of values between low and high values, including high values.lowval - an expression that resolves to a low collation sequence value ...
Posted on Sun, 05 Dec 2021 08:23:18 -0500 by yumico23
1. Procedural sql and embedded sql
1.1 embedded sql
Embedded SQL refers to including SQL statements into programming language. The embedded programming language, such as C / CPP / Java, is called the host language.
For embedded SQL, DBMS generally adopts the precompiled method, that is, the preprocessor of DBMS scans the source progra ...
Posted on Sun, 05 Dec 2021 05:57:36 -0500 by gerkintrigg
1, Functions of SQL language
SQL functionpredicateData definition (DDL)CREATE,DROP,ALTERData query (DQL)SELECTData manipulation (DML)INSERT,UPDATE,DELETEData control (DCL)GRANT,REVOKE,DENY
2, Data types supported by SQL
SQL data types are composed of 13 basic data types, including shaping, single precision, double precision, variable length c ...
Posted on Sun, 05 Dec 2021 03:00:44 -0500 by ineedhelp512