mtx

Models and Transformations, Expressed

A DSL to describe models targeting different technologies:

• postgres database
• gcp/bigquery database
• gcp/spanner database
• protocolbuffers
• golang struct
• csv
• entity–relationship

example Postgres (pg) Database table

db := pg.Database("example")
tab := db.Table("persons")
col := tab.Column("name").Datatype(pg.Text).Doc("what people call you")

// or the short version
col = tab.C("name",pg.Text,"what people call you")

Transforming this table to DDL creation statement in SQL

sql := tab.ToSQL()

then sql:

    -- DROP TABLE persons
CREATE TABLE persons (
    name text NOT NULL -- what people call you
);

Transforming this table to an Entity representing a row.

ent := tab.ToEntity()

The entity ent will have an Attribute name with Datatype basic.String

Transforming this entity to a Go struct

str := golang.ToStruct(ent)

The struct str will have a Field name with Datatype golang.String

Transform this struct to Go source

src := str.ToGo()

then src:

// Persons :
type Persons struct {
    Name string // what people call you
}

how to transform one model to another

A pg model (db.Table) first needs to be converted to an Entity model (basic.Entity). The Entity model can be converted to a Go model (golang.Struct). The Entity model can be modified to drive the conversion to the struct.

• rename
• change datatypes

Each model is using its own types and datatypes. Transformations to and from a selection of model combinations.