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https://github.com/xo/xo

Command line tool to generate idiomatic Go code for SQL databases supporting PostgreSQL, MySQL, SQLite, Oracle, and Microsoft SQL Server
https://github.com/xo/xo

code-generator golang microsoft-sql-server mysql oracle orm postgresql sql sqlite

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Command line tool to generate idiomatic Go code for SQL databases supporting PostgreSQL, MySQL, SQLite, Oracle, and Microsoft SQL Server

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README 

        
# xo



`xo` is a command-line tool to generate _idiomatic_ code for different

languages code based on a database schema or a custom query.





  Installing |

  Building |

  Using |

  Releases




[![Releases][release-status]][Releases]

[![Discord Discussion][discord-status]][discord]



[releases]: https://github.com/xo/xo/releases "Releases"

[release-status]: https://img.shields.io/github/v/release/xo/xo?display_name=tag&sort=semver "Latest Release"

[discord]: https://discord.gg/WDWAgXwJqN "Discord Discussion"

[discord-status]: https://img.shields.io/discord/829150509658013727.svg?label=Discord&logo=Discord&colorB=7289da&style=flat-square "Discord Discussion"



#### Supported languages



At the moment, `xo` only supports [Go](https://golang.org). Support for other

languages will come soon.



#### How it works



In schema mode, `xo` connects to your database and generates code using Go

templates. `xo` works by using database metadata and SQL introspection queries to

discover the types and relationships contained within a schema, and applying a

standard set of base (or customized) Go [templates](templates) against the

discovered relationships.



Currently, `xo` can generate types for tables, enums, stored procedures, and

custom SQL queries for PostgreSQL, MySQL, Oracle, Microsoft SQL Server, and

SQLite3 databases.



> **Note:** While the code generated by xo is production quality, it is not the

> goal, nor the intention for xo to be a "silver bullet," nor to completely

> eliminate the manual authoring of SQL / Go code.



In query mode, `xo` parses your query to generate code from Go templates.

It finds related tables in your database to ensure type safety.



## Database Feature Support



The following is a matrix of the feature support for each database:



|              |     PostgreSQL     |       MySQL        |       Oracle       | Microsoft SQL Server |       SQLite       |

| ------------ | :----------------: | :----------------: | :----------------: | :------------------: | :----------------: |

| Models       | :white_check_mark: | :white_check_mark: | :white_check_mark: |  :white_check_mark:  | :white_check_mark: |

| Primary Keys | :white_check_mark: | :white_check_mark: | :white_check_mark: |  :white_check_mark:  | :white_check_mark: |

| Foreign Keys | :white_check_mark: | :white_check_mark: | :white_check_mark: |  :white_check_mark:  | :white_check_mark: |

| Indexes      | :white_check_mark: | :white_check_mark: | :white_check_mark: |  :white_check_mark:  | :white_check_mark: |

| Stored Procs | :white_check_mark: | :white_check_mark: | :white_check_mark: |  :white_check_mark:  | :white_check_mark: |

| Functions    | :white_check_mark: | :white_check_mark: | :white_check_mark: |  :white_check_mark:  | :white_check_mark: |

| ENUM types   | :white_check_mark: | :white_check_mark: |                    |                      |                    |

| Custom types | :white_check_mark: |                    |                    |                      |                    |



## Installing



`xo` can be installed [via Release][], [via Homebrew][], [via AUR][], [via

Scoop][] or [via Go][]:



[via Release]: #installing-via-release

[via Homebrew]: #installing-via-homebrew-macos-and-linux

[via AUR]: #installing-via-aur-arch-linux

[via Scoop]: #installing-via-scoop-windows

[via Go]: #installing-via-go



### Installing via Release



1. [Download a release for your platform][releases]

2. Extract the `xo` or `xo.exe` file from the `.tar.bz2` or `.zip` file

3. Move the extracted executable to somewhere on your `$PATH` (Linux/macOS) or

   `%PATH%` (Windows)



### Installing via Homebrew (macOS and Linux)



Install `xo` from the [`xo/xo` tap][xo-tap] in the usual way with the [`brew`

command][homebrew]:



```sh

# install

$ brew install xo/xo/xo

```



### Installing via AUR (Arch Linux)



Install `xo` from the [Arch Linux AUR][aur] in the usual way with the [`yay`

command][yay]:



```sh

# install

$ yay -S xo-cli

```



Alternately, build and [install using `makepkg`][arch-makepkg]:



```sh

# clone package repo and make/install package

$ git clone https://aur.archlinux.org/xo-cli.git && cd xo-cli

$ makepkg -si

==> Making package: xo-cli 0.4.4-1 (Sat 11 Nov 2023 02:28:28 PM WIB)

==> Checking runtime dependencies...

==> Checking buildtime dependencies...

==> Retrieving sources...

...

```



### Installing via Scoop (Windows)



Install `xo` using [Scoop](https://scoop.sh):



```powershell

# Optional: Needed to run a remote script the first time

> Set-ExecutionPolicy RemoteSigned -Scope CurrentUser



# install scoop if not already installed

> irm get.scoop.sh | iex



# install xo with scoop

> scoop install xo

```



### Installing via Go



Install `xo` in the usual Go fashion:



```sh

# install latest xo version

$ go install github.com/xo/xo@latest

```



## Quickstart



The following is a quick overview of using `xo` on the command-line:



```sh

# Make an output directory for generated code.

$ mkdir -p models



# Generate code from your Postgres schema. (Default output folder is models)

$ xo schema postgres://user:pass@host/dbname



# Generate code from a Microsoft SQL schema using a custom template directory (see notes below)

$ mkdir -p mssqlmodels

$ xo schema mssql://user:pass@host/dbname -o mssqlmodels --src custom/templates



# Generate code from a custom SQL query for Postgres

$ xo query postgres://user:pass@host/dbname -M -B -2 -T AuthorResult << ENDSQL

SELECT

  a.name::varchar AS name,

  b.type::integer AS my_type

FROM authors a

  INNER JOIN authortypes b ON a.id = b.author_id

WHERE

  a.id = %%authorID int%%

LIMIT %%limit int%%

ENDSQL



# Build generated code - verify it compiles

$ go build ./models/

$ go build ./mssqlmodels/

```



## Command Line Options



The following are `xo`'s command-line commands, arguments, and options:



```sh

$ xo --help-long

usage: xo []  [ ...]



Flags:

      --help     Show context-sensitive help (also try --help-long and

                 --help-man).

  -v, --verbose  enable verbose output

      --version  display version and exit



Commands:

  help [...]

    Show help.



  query [] 

    Generate code for a database custom query from a template.



    -s, --schema=            database schema name

    -t, --template=go              template type (createdb, dot, go, json, yaml;

                                   default: go)

    -f, --suffix=             file extension suffix for generated files

                                   (otherwise set by template type)

    -o, --out=models               out path (default: models)

    -a, --append                   enable append mode

    -S, --single=            enable single file output

    -D, --debug                    debug generated code (writes generated code

                                   to disk without post processing)

    -Q, --query=""                 custom database query (uses stdin if not

                                   provided)

    -T, --type=              type name

        --type-comment=""          type comment

    -F, --func=              func name

        --func-comment=""          func comment

    -M, --trim                     enable trimming whitespace

    -B, --strip                    enable stripping type casts

    -1, --one                      enable returning single (only one) result

    -l, --flat                     enable returning unstructured values

    -X, --exec                     enable exec (no introspection performed)

    -I, --interpolate              enable interpolation of embedded params

    -L, --delimiter=%%             delimiter used for embedded params (default:

                                   %%)

    -Z, --fields=           override field names for results

    -U, --allow-nulls              allow result fields with NULL values

    -d, --src=               template source directory

    -2, --go-not-first             disable package comment (ie, not first

                                   generated file)

        --go-int32=int             int32 type (default: int)

        --go-uint32=uint           uint32 type (default: uint)

        --go-pkg=            package name

        --go-tag="" ...            build tags

        --go-import="" ...         package imports

        --go-uuid=            uuid type package

        --go-custom=         package name for custom types

        --go-conflict=Val          name conflict suffix (default: Val)

        --go-initialism= ...  add initialism (i.e ID, API, URI)

        --go-esc=none ...          escape fields (none, schema, table, column,

                                   all; default: none)

    -g, --go-field-tag=       field tag

        --go-context=only          context mode (disable, both, only; default:

                                   only)

        --go-inject=""             insert code into generated file headers

        --go-inject-file=    insert code into generated file headers from

                                   a file

        --go-legacy                enables legacy v1 template funcs

        --go-enum-table-prefix     enables table name prefix to enums

        --json-indent="  "         indent spacing

        --json-ugly                disable indentation



  schema [] 

    Generate code for a database schema from a template.



    -s, --schema=            database schema name

    -t, --template=go              template type (createdb, dot, go, json, yaml;

                                   default: go)

    -f, --suffix=             file extension suffix for generated files

                                   (otherwise set by template type)

    -o, --out=models               out path (default: models)

    -a, --append                   enable append mode

    -S, --single=            enable single file output

    -D, --debug                    debug generated code (writes generated code

                                   to disk without post processing)

    -k, --fk-mode=smart            foreign key resolution mode (smart, parent,

                                   field, key; default: smart)

    -i, --include= ...       include types ()

    -e, --exclude= ...       exclude types/fields ([.])

    -j, --use-index-names          use index names as defined in schema for

                                   generated code

    -d, --src=               template source directory

        --createdb-fmt=      fmt command (default:

                                   /home/ken/.npm-global/bin/sql-formatter)

        --createdb-fmt-opts= ...

                                   fmt options (default: -u, -l={{ . }}, -i=2,

                                   --lines-between-queries=2)

        --createdb-constraint      enable constraint name in output (postgres,

                                   mysql, sqlite3)

        --createdb-escape=none     escape mode (none, types, all; default: none)

        --createdb-engine=""       mysql table engine (default: InnoDB)

        --createdb-trim-comment    trim leading comment from views and procs

                                   (--no-createdb-trim-comment)

        --dot-defaults="" ...      default statements (default: node

                                   [shape=none, margin=0])

        --dot-bold                 bold header row

        --dot-color=""             header color (default: lightblue)

        --dot-row=""               row value template (default: {{ .Name }}: {{

                                   .Type.Type }})

        --dot-direction            enable edge directions

    -2, --go-not-first             disable package comment (ie, not first

                                   generated file)

        --go-int32=int             int32 type (default: int)

        --go-uint32=uint           uint32 type (default: uint)

        --go-pkg=            package name

        --go-tag="" ...            build tags

        --go-import="" ...         package imports

        --go-uuid=            uuid type package

        --go-custom=         package name for custom types

        --go-conflict=Val          name conflict suffix (default: Val)

        --go-initialism= ...  add initialism (i.e ID, API, URI)

        --go-esc=none ...          escape fields (none, schema, table, column,

                                   all; default: none)

    -g, --go-field-tag=       field tag

        --go-context=only          context mode (disable, both, only; default:

                                   only)

        --go-inject=""             insert code into generated file headers

        --go-inject-file=    insert code into generated file headers from

                                   a file

        --go-legacy                enables legacy v1 template funcs

        --go-enum-table-prefix     enables table name prefix to enums

        --json-indent="  "         indent spacing

        --json-ugly                disable indentation

        --postgres-oids            enable postgres OIDs



  dump [] 

    Dump internal templates to path.



    -t, --template=go   template type (createdb, dot, go, json, yaml; default:

                        go)

    -f, --suffix=  file extension suffix for generated files (otherwise set

                        by template type)

```



## About Base Templates



`xo` provides a set of generic "base" [templates](templates) for each of the

supported databases, but it is understood these templates are not suitable for

every organization or every schema out there. As such, you can author your own

custom templates, or modify the base templates available in the `xo` source

tree, and use those with `xo` by a passing a directory path via the `--src`

flag.



For non-trivial schemas, custom templates are the most practical, common, and

best way to use `xo` (see below quickstart and related example).



### Custom Template Quickstart



The following is a quick overview of copying the base templates contained in

the `xo` project's [`templates/`](templates) directory, editing to suit, and

using with `xo`:



```sh

# Create a working directory

$ mkdir -p my-tpl



# Dump an embedded template to disk

$ xo dump -t createdb my-tpl



# edit base template files

$ vi my-tpl/*.go.tpl



# see command line options for the template

$ xo schema --src my-tpl --help



# generate a schema using the custom template

$ xo schema --src my-tpl -o models postgres://user:pass@host/db

```



See the Custom Template example below for more information on adapting the base

templates in the `xo` source tree for use within your own project.



### Storing Project Templates



Ideally, custom templates for your project/schema should be stored alongside

your project. and generated as part of an automated build pipeline using `go

generate`:



```sh

# Add to custom xo command to go generate:

$ tee -a gen.go << END

package mypackage



//go:generate xo postgres://user:pass@host/db -o models --src templates

END



# Run go generate

$ go generate



# Add custom templates and gen.go to project

$ git add templates gen.go && git commit -m 'Adding custom xo templates for models'

```



> **Note**: via the `--template`/`-t` parameter of `xo dump` you can generate

> other templates with `xo`. The default template is the `go` template.



### Template Language/Syntax



`xo` templates are standard Go text templates. Please see the [documentation

for Go's standard `text/template` package](https://pkg.go.dev/text/template)

for information concerning the syntax, logic, and variable use within Go

templates.



### Template Context and File Layout



The contexts (ie, the `.` identifier in templates) made available to custom

templates can be found in [templates/types.go](templates/types.go)

(see below table for more information on which file uses which type).



Each language, has its own set of templates for `$TYPE` and are

available in the [templates/](templates).



|        Template File        | [Type](templates/types.go) | Description                                                                            |

| :-------------------------: | :------------------------: | -------------------------------------------------------------------------------------- |

|        hdr.xo.\*.tpl        |                            | Base template. Executed with content for a template.                                   |

|        db.xo.\*.tpl         |                            | Package level template with base types and interface data. Generated once per package. |

|    schema/enum.xo.\*.tpl    |            Enum            | Template for schema enum type definitions. Generates types and related methods.        |

| schema/foreignkey.xo.\*.tpl |         ForeignKey         | Template for foreign key relationships. Generates related method.                      |

|   schema/index.xo.\*.tpl    |           Index            | Template for schema indexes. Generates related method.                                 |

|    schema/proc.xo.\*.tpl    |            Proc            | Template to generate functions to call defined stored procedures in the db.            |

|  schema/typedef.xo.\*.tpl   |            Type            | Template for schema table/views.                                                       |

|   query/custom.xo.\*.tpl    |           Query            | Template for custom query execution.                                                   |

|   query/typedef.xo.\*.tpl   |            Type            | Template for custom query's generated type.                                            |



For example, Go has [`templates/gotpl/schema/foreignkey.xo.go.tpl`](templates/gotpl/schema/foreignkey.xo.go.tpl)

which defines the template used by `xo` for generating a function to get the

foreign key type in Go. The templates are designed to be Database agnostic, so

they are used for both PostgreSQL and Microsoft SQL the same, and all other

supported database types. The template is passed a different instance of

`templates.ForeignKey` instance (for each foreign key in a table). To get the

`Name` field in from `ForeignKey`, the template can use ` {{ .Data.Name }}`, or

any other field similarly.



## Examples



### Example: End-to-End



Please see the [booktest example](_examples/booktest) for a full end-to-end

example for each supported database, showcasing how to use a database schema

with `xo`, and the resulting code generated by `xo`.



Additionally, please see the [`northwind`](_examples/northwind) and

[`django`](_examples/django) for a demonstration of running `xo` against larger

schema and against databases from other frameworks. Please note that these

examples are works in progress, and may not work properly in all scenarios.



### Example: Ignoring Fields



Sometimes you may wish to have the database manage the values of columns

instead of having them managed by code generated by `xo`. As such, when you

need `xo` to ignore fields for a database schema, you can use the `-e` or

`--exclude` flag. For example, a common use case is to define a table with

`created_at` and/or `modified_at` timestamps fields, where the database is

responsible for setting column values on `INSERT` and `UPDATE`, respectively.



Consider the following PostgreSQL schema where a `users` table has a

`created_at` and `modified_at` field, where `created_at` has a default value of

`now()` and where `modified_at` is updated by a trigger on `UPDATE`:



```postgresql

CREATE TABLE users (

  id          SERIAL PRIMARY KEY,

  name        text NOT NULL DEFAULT '' UNIQUE,

  created_at  timestamptz   default now(),

  modified_at timestamptz   default now()

);



CREATEOR REPLACE FUNCTION update_modified_column() RETURNS TRIGGER AS $$

BEGIN

    NEW.modified_at= now();

RETURN NEW;

END;

$$language 'plpgsql';



CREATE TRIGGER update_users_modtime BEFORE UPDATE ON users

  FOR EACH ROW EXECUTE PROCEDURE update_modified_column();

```



We can ensure that these columns are managed by PostgreSQL and not by the

application logic but by `xo` by passing the `--exclude` or `-e` flag:



```sh

# Ignore special fields

$ xo schema postgres://user:pass@host/db -e users.created_at -e users.modified_at

# or, To ignore these fields in all tables

$ xo schema postgres://user:pass@host/db -e *.created_at -e *.modified_at

```



### Example: Custom Template -- adding a `GetMostRecent` lookup for all tables (Go)



Often, a schema has a common layout/pattern, such as every table having a

`created_at` and `modified_at` field (as in the PostgreSQL schema in the

previous example). It is then a common use-case to have a `GetMostRecent`

lookup for each table type, retrieving the most recently modified rows for each

table (up to some limit, N).



To accomplish this with `xo`, we will need to create our own set of custom

templates, and then add a `GetMostRecent` lookup to the `.type.go.tpl`

template.



First, we dump the base `xo` Go template:



```sh

$ mkdir -p my-tpl



$ xo dump my-tpl

```



We can now modify the templates to suit our specific schema, adding lookups,

helpers, or anything else necessary for our schema.



To add a `GetMostRecent` lookup, we edit our copy of the `typedef.xo.go.tpl`

template:



```sh

$ vi templates/gotpl/schema/typedef.xo.go.tpl

```



And add the following templated `GetMostRecent` func at the end of the file:



```go

// GetMostRecent{{ $type.Name }} returns n most recent rows from '{{ $table }}',

// ordered by "created_at" in descending order.

func GetMostRecent{{ $type.Name }}(ctx context.Context, db DB, n int) ([]*{{ $type.Name }}, error) {

    const sqlstr = `SELECT ` +

        `{{ $type.Fields "created_at" "modified_at" }}` +

        `FROM {{ $table }} ` +

        `ORDER BY created_at DESC LIMIT $1`



    rows, err := db.QueryContext(ctx, sqlstr, n)

    if err != nil {

        return nil, logerror(err)

    }

    defer rows.Close()



    // load results

    var res []*{{ $type.Name }}

    for rows.Next() {

        {{ $short }} := {{ $type.Name }}{

        {{- if $type.PrimaryKey }}

            _exists: true,

        {{ end -}}

        }

        // scan

        if err := rows.Scan({{ fieldnames $type.Fields (print "&" $short) }}); err != nil {

            return nil, logerror(err)

        }

        res = append(res, &{{ $short }})

    }

    return res, nil

}

```



We can then use the templates in conjunction with `xo` to generate our "model"

code:



```sh

$ xo schema postgres://user:pass@localhost/dbname --src templates/

```



There will now be a `GetMostRecentUsers` func defined in `models/user.xo.go`,

which can be used as follows:



```go

db, err := dburl.Open("postgres://user:pass@localhost/dbname")

if err != nil { /* ... */ }



// retrieve 15 most recent items

mostRecentUsers, err := models.GetMostRecentUsers(context.Background(), db, 15)

if err != nil { /* ... */ }

for _, user := range users {

    log.Printf("got user: %+v", user)

}

```



## Using SQL Drivers



Please note that the base `xo` templates do not import any SQL drivers. It is

left for the user of `xo`'s generated code to import the actual drivers. For

reference, these are the expected drivers to use with the code generated by

`xo`:



| Database (driver)            | Package                                                                    |

| ---------------------------- | -------------------------------------------------------------------------- |

| PostgreSQL (postgres)        | [github.com/lib/pq](https://github.com/lib/pq)                             |

| SQLite3 (sqlite3)            | [github.com/mattn/go-sqlite3](https://github.com/mattn/go-sqlite3)         |

| MySQL (mysql)                | [github.com/go-sql-driver/mysql](https://github.com/go-sql-driver/mysql)   |

| Microsoft SQL Server (mssql) | [github.com/microsoft/go-mssqldb](https://github.com/microsoft/go-mssqldb) |

| Oracle (ora)                 | [github.com/sijms/go-ora/v2](https://github.com/sijms/go-ora/v2)           |



Additionally, please see below for usage notes on specific SQL database

drivers.



### MySQL (mysql)



If your schema or custom query contains table or column names that need to be

escaped using any of the `--escape-*` options, you must pass the `sql_mode=ansi`

option to the MySQL driver:



```sh

$ xo --escape-all 'mysql://user:pass@host/?parseTime=true&sql_mode=ansi' -o models

```



And when opening a database connection:



```go

db, err := dburl.Open("mysql://user:pass@host/?parseTime=true&sql_mode=ansi")

```



Additionally, when working with date/time column types in MySQL, one should

pass the `parseTime=true` option to the MySQL driver:



```sh

$ xo schema 'mysql://user:pass@host/dbname?parseTime=true' -o models

```



And when opening a database connection:



```go

db, err := dburl.Open("mysql://user:pass@host/dbname?parseTime=true")

```



### SQLite3 (sqlite3)



While not required, one should specify the `loc=auto` option when using `xo`

with a SQLite3 database:



```sh

$ xo schema 'file:mydatabase.sqlite3?loc=auto' -o models

```



And when opening a database connection:



```go

db, err := dburl.Open("file:mydatabase.sqlite3?loc=auto")

```



## About Primary Keys



For row inserts `xo` determines whether the primary key is

automatically generated by the DB or must be provided by the application for the

table row being inserted. For example a table that has a primary key that is

also a foreign key to another table, or a table that has multiple primary keys

in a many-to-many link table, it is desired that the application provide the

primary key(s) for the insert rather than the DB.



`xo` will query the schema to determine if the database provides an automatic

primary key and if the table does not provide one then it will require that the

application provide the primary key for the object passed to the Insert method.

Below is information on how the logic works for each database type to determine

if the DB automatically provides the PK.



### PostgreSQL Auto PK Logic



- Checks for a sequence that is owned by the table in question.



### MySQL Auto PK Logic



- Checks for an autoincrement row in the information_schema for the table in

  question.



### SQLite Auto PK Logic



- Checks the SQL that is used to generate the table contains

  the _AUTOINCREMENT_ keyword.

- Checks that the table was created with the primary key type of _INTEGER_.



If either of the above conditions are satisfied then the PK is determined to be

automatically provided by the DB. For the case of integer PK's when you want to

override that the PK be manually provided then you can define the key type as

_INT_ instead of _INTEGER_, for example as in the following many-to-many link

table:



```sql

  CREATE TABLE site_contacts (

  contact_id	INT NOT NULL,

  site_id	INT NOT NULL,

  PRIMARY KEY(contact_id,siteid),

  FOREIGN KEY(contact_id) REFERENCES contacts (contact_id),

  FOREIGN KEY(site_id) REFERENCES sites (site_id)

)

```



### SQL Server Auto PK Logic



- Checks for an identity associated with one of the columns for the table in

  question.



### Oracle Auto PK Logic



`ALWAYS GENERATED` types will be parsed as Auto PK types for Oracle.



## About xo: Design, Origin, Philosophy, and History



`xo` can likely get you 99% "of the way there" on medium or large database

schemas and 100% of the way there for small or trivial database schemas. In

short, xo is a great launching point for developing standardized packages for

standard database abstractions/relationships, and `xo`'s most common use-case is

indeed in a code generation pipeline, ala `stringer`.



### Design



`xo` is **NOT** designed to be an ORM or to generate an ORM. Instead, `xo` is

designed to vastly reduce the overhead/redundancy of (re-)writing types and

funcs for common database queries/relationships -- it is not meant to be

a "silver bullet".



### History



`xo` was originally developed while migrating a large application written in

PHP to Go. The schema in use in the original app, while well-designed, had

become inconsistent over multiple iterations/generations, mainly due to

different naming styles adopted by various developers/database admins over the

preceding years. Additionally, some components had been written in different

languages (Ruby, Java) and had also accumulated significant drift from the

original application and accompanying schema. Simultaneously, a large amount of

growth meant that the PHP/Ruby code could no longer efficiently serve the

traffic volumes.



In late 2014/early 2015, a decision was made to unify and strip out certain

backend services and to fully isolate the API from the original application,

allowing the various components to instead speak to a common API layer instead

of directly to the database, and to build that service layer in Go.



However, unraveling the old PHP/Ruby/Java code became a large headache, as the

code, the database, and the API, all had significant drift -- thus, underlying

function names, fields, and API methods no longer coincided with the actual

database schema, and were named differently in each language. As such, after a

round of standardizing names, dropping cruft, and adding a few relationship

changes to the schema, the various codebases were fixed to match the schema

changes. After that was determined to be a success, the next target was to

rewrite the backend services in Go.



In order to keep a similar and consistent workflow for the developers, the

previous code generator (written in PHP and Twig templates) was modified to

generate Go code. Additionally, at this time, but tangential to the story, the

API definitions were ported from JSON to Protobuf to make use of its code

generation abilities as well.



`xo` is the open source version of that code generation tool, and is the fruits

of those development efforts. It is hoped that others will be able to use and

expand `xo` to support other databases -- SQL or otherwise -- and that `xo` can

become a common tool in any Go developer's toolbox.



### Goals



Part of `xo`'s goals is to avoid writing an ORM, or an ORM-like in Go, and to

instead generate static, type-safe, fast, and idiomatic Go code across

languages and databases. Additionally, the `xo` developers are of the opinion

that relational databases should have proper, well-designed relationships and

all the related definitions should reside within the database schema itself:

ie, a "self-documenting" schema. `xo` is an end to that pursuit.



## Related Projects



- [dburl](https://github.com/xo/dburl) - a Go package providing a standard, URL

  style mechanism for parsing and opening database connection URLs

- [usql](https://github.com/xo/usql) - a universal command-line interface for

  SQL databases



### Other Projects



The following projects work with similar concepts as xo:



#### Go Generators



- [ModelQ](https://github.com/mijia/modelq)

- [sqlgen](https://github.com/drone/sqlgen)

- [squirrel](https://github.com/Masterminds/squirrel)

- [scaneo](https://github.com/variadico/scaneo)

- [acorn](https://github.com/willowtreeapps/acorn) and

  [rootx](https://github.com/willowtreeapps/rootx) ([read overview here](http://willowtreeapps.com/blog/go-generate-your-database-code/))



#### Go ORM-likes



- [sqlc](https://github.com/relops/sqlc)



[homebrew]: https://brew.sh/

[xo-tap]: https://github.com/xo/homebrew-xo

[aur]: https://aur.archlinux.org/packages/xo-cli

[arch-makepkg]: https://wiki.archlinux.org/title/makepkg

[yay]: https://github.com/Jguer/yay