Category: Database

The database is a warehouse that organizes, stores and manages data according to the data structure. It was created more than 60 years ago. With the development of information technology and the market, especially after the 1990s, data management is no longer just It is to store and manage data, and transform it into various data management methods required by users. There are many types of databases, from the simplest tables that store various data to large-scale database systems that can store massive amounts of data. They have been widely used in all aspects.

DDL operation table structure

DDL operation table structure: CRUD One, C (create) create 　　1, create table create table table name(
Column name 1 data type 1,
Column name 2 data type 2,
Column name 3 data type 3,

September 21, 2021By Simo Mysql Book, DDL, Fork, structureLeave a Comment

PostgreSQL – the inconsistency between the month, Japanese and seconds of the interval data type

I understand why postgresql uses month, day and second fields to represent the sql interval data type. If it involves daylight saving time adjustments, the length of a month is not always the same.

September 21, 2021By Simo Postgresql between, data, Day, display, inconsistent, Interval, month, PostgreSQL, stopwatch, typeLeave a Comment

Cassandra – Scylladb 2.1 – inconsistent with the materialization view

When deciding on the technology stack of my own product, I decided to use the scyllaDB database because of its impressive performance.

For local development , I set up Cassandra on my Macbook

September 21, 2021By Simo Nosql 2.1, Cassandra, inconsistent, materialization, Scylladb, viewLeave a Comment

PostgreSQL only selects the letters in the column

So I have this column that contains the street address and house number, and they are all stored in the same column.

For example: Boulevard 123

How can I do this with reg expressions?

September 21, 2021By Simo Postgresql Column, letters, PostgreSQL, selectLeave a Comment

RDBMS – Relationship between reasonable export and non-relational data

For various reasons, we have different products that rely on relational databases, which are basically the transactional nature of operations (atomicity, consistency, etc.). This will not change so

September 21, 2021By Simo Nosql data, export, non-, RDBMS, reasonable, Related, relationshipLeave a Comment

35 application scenarios in the NOSQL database

【Sumeng is committed to becoming the most outstanding data science community, focusing on big data, analysis and mining, and data visualization Field, business scope: offline activities, online cou

September 21, 2021By Simo Nosql application, database, NOSQL, sceneLeave a Comment

Looking for the build forest (with recursive, postgreSQL 9.5)

I have a table of identities (ie aliases) for any number of people. Each row has a previous name and a new name. In production, there are approximately 1M rows. For example:

id, old, new
—

September 21, 2021By Simo Postgresql 9.5, build, forest, Looking for, PostgreSQL, RecursiveLeave a Comment