of your project results the terms aren' weighted by their score in this casebut it already provides nice representation of the findings many improvements are possible for your applicationespecially in the area of data preparation but diving into all the possibilities here would take us too farthus we've come to the end of this in the next one we'll take look at streaming data summary in this you learned the followingnosql stands for "not only structured query languageand has arisen from the need to handle the exponentially increasing amounts and varieties of dataas well as the increasing need for more diverse and flexible schemas such as network and hierarchical structures handling all this data requires database partitioning because no single machine is capable of doing all the work when partitioningthe cap theorem appliesyou can have availability or consistency but never both at the same time relational databases and graph databases hold to the acid principlesatomicityconsistencyisolationand durability nosql databases generally follow the base principlesbasic availabilitysoft stateand eventual consistency the four biggest types of nosql databases key-value stores--essentially bunch of key-value pairs stored in database these databases can be immensely big and are hugely versatile but the data complexity is low well-known example is redis wide-column databases--these databases are bit more complex than keyvalue stores in that they use columns but in more efficient way than regular rdbms would the columns are essentially decoupledallowing you to retrieve data in single column quickly well-known database is cassandra document stores--these databases are little bit more complex and store data as documents currently the most popular one is mongodbbut in our case study we use elasticsearchwhich is both document store and search engine graph databases--these databases can store the most complex data structuresas they treat the entities and relations between entities with equal care this complexity comes at cost in lookup speed popular one is neo jbut graphx ( graph database related to apache sparkis winning ground elasticsearch is document store and full-text search engine built on top of apache lucenethe open source search engine it can be used to tokenizeperform aggregation queriesperform dimensional (facetedqueriesprofile search queriesand much more