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This article is about Learning Guide for Big Data Specialists from Zero (Full Upgrade) Java concurrency supplement for. 1 New way 1: Implement Callable interface Callable is more powerful than Runnable Can have a return value compared to the run() methodMethod can throw an exceptionReturn values supporting genericsYou need to use the Futur ...

SQL Server 2008 database structure System database master A database that records all system level information of the SQL Server systemmsdbTemplate database for all user databases and tempdb databasemodelUsed by SQL Server agent to schedule alerts and jobstempGlobal resources available to all users connected to the SQL Server instance, save a ...

This article is about Learning Guide for Big Data Specialists from Zero (Full Upgrade) ClickHouse: Partial supplement. Table Engine 4.1 Use of Table Engine The table engine is a feature of ClickHouse. It can be said that the table engine determines how the underlying data is stored. These include: _How and where data is stored, where it i ...

Database foundation Database: a collection that stores, maintains, and manages dataDataBase Management System (DBMS) Common database management system Oracle Relational type MySQL Relational type DB2 Microsoft SQL Server Three paradigms First normal form (1NF): no duplicate columns;The second normal form (2NF): attributes are complete ...

ELK learning 1, What is it Elasticsearch is an open source distributed search engine. Its features include: distributed, zero configuration, automatic discovery, automatic index fragmentation, index copy mechanism, restful style interface, multi data sources, automatic search load, etc.Logstash is a completely open source tool. It can collect ...

Hadoop cluster construction 1, Environmental preparation (prepare a formwork machine) 1.1 template machine configuration - Hadoop 100 The template machine does not move. In order to facilitate cloning later, new nodes are added directly Virtual machine requirements: 4G memory, 50G hard disk, CentOS7, minimum installation Here, Hadoop 100 i ...

Common database objects What is a sequence? Sequence: a database object that can be used by multiple users to generate unique values Automatically provide unique values Shared object It is mainly used to provide primary key values Loading sequence values into memory can improve access efficiency CREATE SEQUENCE statement Define sequence: CRE ...

Rotation chart It is often located on the home page and used as a large picture for activity promotion. It can be played automatically by clicking the left and right switch button, or by clicking the small dot on the picture   Tab Toggle It is used to click different labels or titles to display different contents   Form Validation ...

Start learning big data again - Hbase - day 56 Phoenix Phoenix overview    Hbase is suitable for storing a large number of NOSQL data with low requirements for relational operations. Due to the limitations of Hbase design, it is not possible to directly use the native API to perform the operations such as condition judgment a ...

Tip: the following is the main content of this article. The following cases can be used for reference 1, Introduction 1.1 what are the existing data storage methods? ① Java programs store data (variables, objects, arrays, collections), which are stored in memory and belong to transient state storage. ② File stores data, which is ...