Types

Data types are the categories of data values that can be stored, processed, and retrieved by a programming language. Common data types include numbers (integers, floats, complex), characters (single characters, strings), booleans (true/false), dates, times, and null/undefined values. Additionally, derived data types include arrays (ordered collections) and objects (unordered collections of named values). Each data type has its own set of properties and operations that can be performed on it, such as comparison, arithmetic, and casting. Understanding data types is crucial for writing effective and efficient code that accurately processes and manipulates data.

Having a universal type system allows for each integration between various services across technology stacks, programming language, and system boundaries.

Standard Data Types

All the blocks in kis.ai, support standard data types and these form the foundation for strong type-safe way to integrate services.

Data Type	Description	Postgres	GraphQL	JSON
klid	kis.ai ulid, used as identity field for users, delegates, bots and agents	char(27)	ID	string
ulid	ulid is better suited than guid as its lexicographically sortable	char(26)	ID	string
byte	8 bits of data, typical used for storing flag information	byte	Byte	integer
bytes	array of bytes, useful for binary data	bytea	[Byte]	array(integers)
int	32-bit int	int	Int	integer
bigint	64-bit int	bigint	Int	integer
double	double precision floating point number	float8	Float	double
boolean	boolean values, true or false	boolean	Boolean	boolean
date	date	date	String	string
datetime	timestamp without timezone, no timezone calculations performed	int	Int	string
timestamp	timestamp with timezone information	timestamptz	String	string
string	variable length characters, useful for storing text information. This is the default datatype	text	String	string
object	an object with properties, typically used to store embeddables	jsonb	object	array
array(<type>)	array of values of other primitive data types or objects	jsonb	array	enum
enum	native enum datatype	int	Int	string

Custom Data Types

In some situations, new types need to be created. Data API allows creation of custom data types. Each custom data types will have encode and decode functions for encoding data before storing in database and decoding after reading from the database.

Here is an example where a binary data is encoded into base64 and being stored as text in the database.

Encoding and Decoding by Database

/data/datastores/alm/types-db.yaml

#custom image data type encode/decode done by database
types:
- name: image
  database: postgres
  dbtype: text # need to give database specific type, here in this example for postgres
  type: db # means the encoding and decoding will be done by database. The other option is app, where app takes care of encoding and decoding.
  encode: encode({{data}}, 'base64') # converts binary byte array into base64 string
  decode: decode({{field}}, 'base64') # converts base64 text into binary byte array

Encoding and Decoding by Application

/data/datastores/alm/types-app.yaml

#custom image data type encode/decode done by Data API service
types:
- name: image
  database: postgres
  dbtype: text # need to give database specific type, here in this example for postgres
  type: app # means the encoding and decoding will be done by app.
  encode: base64 # converts binary byte array into base64 string
  decode: base64 # converts base64 text into binary byte array

Symbols

In more advanced use cases, some User-Defined Functions (UDFs) or functions provided by database extensions can be exposed to be used by developers. Symbols are added to datastore, to enable their usage in the database. Symbols are database specific, like types.

/data/datastores/alm/symbols.yaml

symbols:
  postgres:
    system:
      count: count({{field}})
      min: min({{field}})
      max: max({{field}})
    udf:
      tax: tax({{1}}, {{2}})
    vars:
    - customername

User-Defined Functions

Database specific User-Defined Functions can be added to a datastore. This are advanced features, and should be avoided as much as possible.

/data/datastores/alm/functions.yaml

functions:
- name: tax
  database: postgres
  definition: |
    CREATE OR REPLACE FUNCTION tax( amount NUMERIC, tax NUMERIC)
    RETURNS NUMERIC AS $$
    BEGIN
      RETURN amount + (amount * tax);
    END; $$
    LANGUAGE plpgsql;