전체 글
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DDL, DML, DCL, and TCLDB/RDB 2020. 2. 23. 23:29
1. Overview 2. Description 2.1 Data Definition Language (DDL) DDL is the short name of Data Definition Language, which deals with database schemas and descriptions, of how the data should reside in the database. CREATE – to create a database and its objects like (table, index, views, stored procedure, function, and triggers) ALTER – alters the structure of the existing database DROP – delete obj..
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Clustered and Non clustered indexDB/RDB 2020. 2. 23. 23:00
1. Overview With a clustered index the rows are stored physically on the disk in the same order as the index. Therefore, there can be only one clustered index. With a non clustered index there is a second list that has pointers to the physical rows. You can have many non clustered indices, although each new index will increase the time it takes to write new records. It is generally faster to rea..
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Access ModifierStaticPL/JAVA 2020. 2. 23. 22:50
1. Overview 2. Example 2.1 private class A{ private int data=40; private void msg(){System.out.println("Hello java");} } public class Simple{ public static void main(String args[]){ A obj=new A(); System.out.println(obj.data);//Compile Time Error obj.msg();//Compile Time Error } } class A{ private A(){}//private constructor void msg(){System.out.println("Hello java");} } public class Simple{ pub..
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Unit Testing vs Integration TestingTestMetric 2020. 2. 23. 22:30
1. Overview Integration testing will help to verify the overall system after developing the different modules. When issues observed in the integration test, the unit testing results for specific functionality will help to fix the issue. As a result, both Unit testing and Integration testing are equally important. 2. Comparison Unit Testing Integration Testing Unit testing is a type of testing to..
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WebSockets vs Long PollingWeb/Protocol 2020. 2. 23. 22:21
1. Overview Sometimes we need information from our servers as soon as it’s available. The usual AJAX request/response we’re all used to doesn’t keep the connection open for this sort of use case. Instead, we need a push-based method like WebSockets, Long Polling, Server-sent events (SSE) and more recently HTTP2 push. In this article, we compare two methods: WebSockets and Long Polling. 2. Long P..
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Database ScalingModeling/TheoremParadigm 2020. 2. 23. 20:50
1. Methods of Scaling 1.1 Vertical Scaling (Scale-up) In Vertical Scaling, we increase the CPU, RAM, and Storage or buy a more robust server in order to support more traffic and load on our database server. 1.2 Horizontal Scaling (Scale-out) In Horizontal Scaling we add more systems with the smaller configuration in terms of CPU, RAM and Storage to distribute the traffic or load across these sys..
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MySQL ScalingDB/RDB 2020. 2. 23. 20:48
1. Overview By default, the MySQL can be scaled either using Vertical or Hybrid approaches but not fully Horizontal approach. 1.1 What is Scaling, Why and When to use In simple words, Scaling is making your database handle more traffic or load for reading and write queries 2. Master-Slave approach Generally, we tend to create a Master-Slave architecture and route all the write queries on the Mas..
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MongoDB TransactionsDB/Nosql 2020. 2. 23. 20:18
1. Overview With multi-document ACID transactions in MongoDB, you get the only database that fully combines the power of the document model and a distributed systems architecture with ACID guarantees. Through snapshot isolation, transactions provide a consistent view of data and enforce all-or-nothing execution to maintain data integrity, even across sharded clusters. 2. Description Now for a tr..