Tarantool Querying Questions

Question

I have the following data structure format:

unix/:/var/run/tarantool/tarantool.sock> s:format()
---
- [{'name': 'id', 'type': 'unsigned'}, {'name': 'version', 'type': 'array'}, {'name': 'data',
    'type': 'array'}]
...

And I have the following data already inside it:

unix/:/var/run/tarantool/tarantool.sock> s:select{}
---
- - [0, [[21, 'action123'], [12, 'actionXYZ'], [11, 'actionABC']], [['actionXYZ',
        'SOME_JAVASCRIPT_CONTENT']]]
  - [1, [[33, 'action123'], [12, 'baseXYZ'], [11, 'baseABC']], [['bas123', 'SOME_CSS_CONTENT']]]
...

I have read through the references and documentation and I'm a bit lost on completing the following:

1. What's the "WHERE" equivalent? ie. Select to find entries that have a version of 12

   Not seeing applicable examples in https://www.tarantool.io/en/doc/2.2/reference/reference_lua/box_space/#lua-function.space_object.select

2. List items with the field names (so I know what block I'm looking at). In a way, sort of like having "column headers" in your results in SQL.

   I have named tuples in my format() - how can I see these names when I'm querying data?

   {'name': 'id', 'type': 'unsigned'}, {'name': 'version', 'type': 'array'}, {'name': 'data', 'type': 'array'}]

3. Pretty print! (preferably yaml)

   I tried using https://www.tarantool.io/en/doc/2.2/reference/reference_lua/yaml/ to wrap around my select statements, but nothing was working.

Answer 1

1. You need to use indexes for imperative effective queries, look here:

https://www.tarantool.io/en/doc/2.2/reference/reference_lua/box_space/#lua-function.space_object.create_index

https://www.tarantool.io/en/doc/2.2/reference/reference_lua/box_index/

2. use tuple:tomap():

https://www.tarantool.io/en/doc/2.2/reference/reference_lua/box_tuple/#lua-function.tuple_object.tomap

3. It depends on where do you want it pretty. You may have to tune yaml settings, or simply chain tomap calls:

tarantool> box.space.TEST:pairs():map(function(x) return x:tomap({names_only=true}) end):totable()
---
- - COLUMN1: 1
    COLUMN2: a
  - COLUMN1: 13
    COLUMN2: a
  - COLUMN1: 1000
    COLUMN2: a