Catalytic: ScyllaDB and Cassandra Object-Relation Mapper

This library contains several crates with the following features:

Automatic map tables to Rust structs: catalytic_table_to_struct. See Usage. See the generated dir for the generated code.
Compile time checked queries: catalytic_macro (catalytic_macro::query). See Usage.
Plugin derive macro to generate business logic: catalytic_macro (catalytic_macro::mirror)
Automatic JSON mapping. When there is a column with type text, you can implement the Transformer trait and map it to a type that implements serde::Serialize and serde::Deserialize
All queries are executed as a prepared statement
Support for Materialized Views (and mapping between the base table if the columns are the same)

Not all types are supported yet due to scylladb/scylla-rust-driver#104

Query types

Depending on a query, a certain query type can be derived. These can be found here. These are the commonly used query types:

SelectMultiple: Can be used as an iterator to iterate over the rows
SelectUnique: Selects an optional unique row by full primary key
SelectUniqueExpect: Same as SelectUnique, but fails if the row doesn't exist
SelectUniqueExpect with Count as entity type: has the special select_count method for queries like "select count(*) from ..."

There are also structs for CRUD operations.

Usage

Automatic map tables to Rust

You can see an example on how to generate Rust structs in the example dir.

In the build.rs file the Transformer trait is implemented and used for json mapping
In the generated dir you can see the generated structs

How to implement it yourself (step-by-step guide how to mimic the example crate):

Add a build-dependency: catalytic_table_to_struct = "0.1"
Create a build.rs file
Optionally implement the Tranformer trait (or use DefaultTransformer)
Call catalytic_table_to_struct::generate
Build the project

An example of the structure of the generated code for table 'child' is:

Child: a struct with owned values. Can be converted to ChildRef, PrimaryKey and PrimaryKeyRef
ChildRef: a struct where the values are all borrowed. This struct can perform insertions. Can be converted to Child, PrimaryKey and PrimaryKeyRef
PrimaryKey: a struct which holds the owned values of the primary key fields of Child. Can be converted to PrimaryKeyRef.
PrimaryKeyRef: a struct where the values are all borrowed. This struct can perform updates, deletions and selects. Can be converted to PrimaryKey
UpdatableColumn: an enum which holds the enum variants with owned values of columns that can be updated. Can be converted to UpdatableColumnRef.
UpdatableColumnRef: an enum where the values are all borrowed. This is used by PrimaryKeyRef for updates. Can be converted to UpdatableColumn.

Macros

Crate catalytic_macro holds several macros that can be used to ensure compile/type checked queries. Examples on how this can be used can be found in lib.rs, method qmd.

How to implement it yourself:

Add dependency: catalytic_macro = "0.1"
The query macro returns the correct query type for the given query
The query_base_table macro transforms a select query to the materialized view table, to a select query of the base table
mirror and primary_key can be used for other derive macros

Used in production