luis-sousa-pinto/entimport

A tool for generating Ent schema from SQL schema

entimport

entimport is a tool for creating Ent schemas from existing SQL databases. Currently, MySQL and PostgreSQL are supported. The tool can import to ent schema any number of tables, including relations between them.

Installation

Setup A Go Environment

If your project directory is outside GOPATH or you are not familiar with GOPATH, setup a Go module project as follows:

go mod init <project>

Install ent

go install entgo.io/ent/cmd/ent

After installing ent codegen tool, you should have it in your PATH. If you don't find it your path, you can also run: go run entgo.io/ent/cmd/ent <command>

Create Schema Directory

Go to the root directory of your project, and run:

ent init

The command above will create <project>/ent/schema/ directory and the file inside <project>/ent/generate.go

Importing a Schema

Installing and running entimport

go run ariga.io/entimport/cmd/entimport

• For example, importing a MySQL schema with users table:

go run ariga.io/entimport/cmd/entimport -dsn "mysql://root:pass@tcp(localhost:3308)/test" -tables "users"

The command above will write a valid ent schema into the directory specified (or the default ./ent/schema):

.
├── generate.go
└── schema
    └── user.go

1 directory, 2 files

Code Generation:

In order to generate ent files from the produced schemas, run:

go run -mod=mod entgo.io/ent/cmd/ent generate ./schema

# OR `ent` init:

go generate ./ent

If you are not yet familiar with ent, you can also follow the quick start guide.

Usage

entimport  -h

Usage of ./entimport:
  -dsn string
        data source name (connection information), for example:
        "mysql://user:pass@tcp(localhost:3306)/dbname"
        "postgres://user:pass@host:port/dbname"
  -schema-path string
        output path for ent schema (default "./ent/schema")
  -tables value
        comma-separated list of tables to inspect (all if empty)

Examples:

1. Import ent schema from Postgres database

Note: add search_path=foo if you use non public schema.

go run ariga.io/entimport/cmd/entimport -dsn "postgres://postgres:pass@localhost:5432/test?sslmode=disable" 

2. Import ent schema from MySQL database

go run ariga.io/entimport/cmd/entimport -dsn "mysql://root:pass@tcp(localhost:3308)/test"

3. Import only specific tables:

Note: When importing specific tables:
if the table is a join table, you must also provide referenced tables.
If the table is only one part of a relation, the other part won't be imported unless specified.
If the -tables flags is omitted all tables in current database schema will be imported

go run ariga.io/entimport/cmd/entimport -dsn "..." -tables "users,user_friends" 

4. Import to another directory:

go run ariga.io/entimport/cmd/entimport -dsn "..." -schema-path "/some/path/here"

Future Work

• Index support (currently Unique index is supported).
• Support for all data types (for example uuid in Postgres).
• Support for Default value in columns.
• Support for editing schema both manually and automatically (real upsert and not only overwrite)
• Postgres special types: postgres.NetworkType, postgres.BitType, *schema.SpatialType, postgres.CurrencyType, postgres.XMLType, postgres.ArrayType, postgres.UserDefinedType.

Known Caveats:

• Schema files are overwritten by new calls to entimport.
• There is no difference in DB schema between O2O Bidirectional and O2O Same Type - both will result in the same ent schema.
• There is no difference in DB schema between M2M Bidirectional and M2M Same Type - both will result in the same ent schema.
• In recursive relations the edge names will be prefixed with child_ & parent_.
• For example: users with M2M relation to itself will result in:

func (User) Edges() []ent.Edge {
return []ent.Edge{edge.To("child_users", User.Type), edge.From("parent_users", User.Type)}
}

Feedback & Support

For discussion and support, open an issue or join our channel in the gophers Slack.