Programmer Help

preface 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 ...

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 ...

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 ...

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 ...

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 ...

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. Related articles: DBMS_CLOUD PackageOracle Cloud Infrastructure (OCI) : Create an Object Storage BucketOracle Cloud : Autonomous Database (ADW or ATP) - Load Data from an Object Store (DBMS ...

Chapter 5 SQL predicate BETWEEN outline scalar-expression BETWEEN lowval AND highval parameter 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 ...

  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 ...

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 ...