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Default KeyValue

Overview

Default KeyValue is the most simple KeyValue in Valentina DB.

This KeyValue is similar to many third-party KeyValue stores in the sense that it takes your KEY and just index it using default comparator.

In ValentinaDB we have decided to use string-based Keys with binary comparator (simple memcmp() function from C).

CREATE

DROP

You can drop Default KeyValue using

WRITE DATA

Writing data into KeyValue is similar to Table's records operations.

API:

SQL:

  • KEYVALUE keyvalue_name INSERT ( key:value, … )
  • KEYVALUE keyvalue_name UPDATE ( key:value, … )
  • KEYVALUE keyvalue_name UPSERT ( key:value, … )
  • KEYVALUE keyvalue_name DELETE( key, … )
  • KEYVALUE keyvalue_name GET ( key, … )

To understand how they work, imagine that Key is a unique field of the table. Then, it is easy to see that

  • insert will throw an exception on inserting key duplicate;
  • update expects that key already exists and throw an exception if key is not found;
  • upsert is combination of insert and update, and never throws error;
  • delete will throw an exception if the key is not found in the store.

READ DATA

You can read data from KeyValue storage with API or SQL approaches: