reseach
Fact table - numeric result
Dimension table - attributes
DBMS vs RDBMS
DBMS - Data Base Managment System
DBMS - Relational Data Base Managment System
HDFS - Hadoop Database File System
1.storage form:
Data is stored in DBMS as files;
Data is stored in a tabluar form in RDBMS
2.relationship in and among table:
There can be, but there will be no “relation” between the tables, like in a RDBMS. In DBMS, data is generally stored in either a hierarchical form or a navigational form. This means that a single data unit will have one parent node and zero, one or more children nodes. It may even be stored in a graph form, which can be seen in the network model.
In a RDBMS, the tables will have an identifier called primary key. Data values will be stored in the form of tables. The relationships between these data values will be stored in the form of a table as well. Every value stored in the relational database is accessible. This value can be updated by the system. The data in this system is also physically and logically independent.
Traditional DBMS’s limitation
no way to predict how many data will come, are failing to scale up to Big data
NoSQL:
Big Data systems
Labmda architecture
OLAP - Online Analytics Processing - cubes
OLTP - Onine Transactions Processing - tables/views
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