* dialect/sql/schema: file based type store
This PR adds support for a file based type storage when using versioned migrations. The file called `.ent_types` is written to the migration directory alongside the migration files and will be kept in sync for every migration file generation run.
In order to not break existing code, where the type storage might differ for different deployment, global unique ID mut be enabled by using a new option. This will also be raised as an error to the user when attempting to use versioned migrations and global unique ID.
Documentation will be added to this PR once feedback on the code is gathered.
* apply CR
* fix tests
* change format of types file to exclude it from atlas.sum file
* docs and drift test
* apply CR
This will allow us to store information about pk ranges allocated per type in a different location thant the database. This is useful for deterministic pk range computation for things like generating atlas.hcl out of the Ent schema.
What's the problem: Under versioned migration on MySQL 8.0, unique string field would be generated as type varchar(191) instead of varchar(255). This is because in generating migration files by NamedDiff(), sqlDialect's init() method is not called.
Further concern: For init() function, MySQL and Postgres's implementation checks the database version which is what I want. But SQLite's implementation checks the foreign_keys support. So I think there might be a better may to check the database version before doing Diff().
* dialect/sql/schema: add method to create a named versioned migration file
* doc/md: documentation for named versioned migrations
* entc/gen/template/dialect/sql/feature: add NamedDiff method to create named versioned migration files
* all: go generate
* doc/md: apply CR
* dialect/sql/schema: fix go doc
* all: update atlas
* dialect/sql/schema: diff connected DB and defined schema and write changes to migration file
* dialect/sql/schema: use migration directory and formatter directly instead of a planner
* all: update atlas
* cmd: add command to create a new migration file
* entc/gen: generate main.go with migrate diff example
* all: regenerate
* cmd/internal/base: make linter happy
* all: support Go 1.16 in versioned migrations main.go
* entc/gen: put versioned migrations behind feature flag
* all: regenerate
* cmd/ent: driver-prefixed dsn in migrate diff command
* cmd/internal/base: remove prefix from migrate import
* cmd/internal/base: use cobra.CheckErr
* cmd: remove diff command
* entc/gen/template/dialect/sql/feature: remove generated main.go
* all: rebase on master and go mod tidy
* all: regenerate
This is a WIP PR and should be ignored this moment.
It's based on PR #221 created by Erik Hollensbe (He should
get his credit for his work before we land this).
* entc/gen: change name format for edge fks
* dialect/sql/schema: add fixture support for mysql and postgres
* sql/dialect: merge fkcolumn queries to one for the 2 dialects
