Chapter 6

Querying NoSQL Stores


  • Illustrating a few query mechanisms in NoSQL in sample data sets
  • Querying use cases in the context of MongoDB, HBase, and Redis
  • Creating advanced and complex queries in NoSQL
  • Using alternatives for rich querying capabilities without SQL

SQL is possibly the simplest yet most powerful domain-specific language created so far. It is easy to learn because it has a limited vocabulary, unambiguous grammar, and a simple syntax. It is terse and limited in scope but it does precisely what it’s meant to do. It enables you to manipulate structured data sets like a ninja. You can easily filter, sort, dice, and slice the data sets. Based on relations, you can join data sets and create intersections and unions. You can summarize data sets and manipulate them to group by a specific attribute or filter them on the basis of their grouping criteria. There is one limitation, though: SQL is based on relational algebra, which works well with relational databases only. As is evident from its name, there is no SQL with NoSQL.

The absence of SQL does not mean that you need to stop querying data sets. After all, any data is stored to be possibly retrieved and manipulated later. NoSQL stores have their own ways of accessing and manipulating data and you have already seen some of that.

NoSQL should really have been NonRel, implying non-relational. Although the creators and proponents of the so-called NoSQL databases were moved away from relational ...

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