GQT - Go(lang) SQL Templates

Package gqt is a template engine for SQL queries.

It helps to separate SQL code from Go code and permits to compose the queries with a simple syntax.

The template engine is the standard package "text/template".

Why this package? Read more about ORM is the Vietnam of computer science.

Install/update using go get (no dependencies required by gqt):

go get -u github.com/Davmuz/gqt

Benefits

SQL is the best language to write SQL.
Separation between Go and SQL source code (your DB administrator will thank you).
Simpler template syntax for composing queries than writing Go code.
Simplified maintenance of the SQL code.

Compatibility

Go >= 1.6

Usage

Create a template directory tree of .sql files. Here an example template with the definition of three blocks:

-- File /path/to/sql/repository/dir/example.sql
{{define "allUsers"}}
SELECT *
FROM users
WHERE 1=1
{{end}}

{{define "getUser"}}
SELECT *
FROM users
WHERE id=?
{{end}}

{{define "allPosts"}}
SELECT *
FROM posts
WHERE date>=?
{{if ne .Order ""}}ORDER BY date {{.Order}}{{end}}
{{end}}

Then, with Go, add the directory to the default repository and execute the queries:

// Setup
gqt.Add("/path/to/sql/repository/dir", "*.sql")

// Simple query without parameters
db.Query(gqt.Get("allUsers"))
// Query with parameters
db.QueryRow(gqt.Get("getuser"), 1)
// Query with context and parameters
db.Query(gqt.Exec("allPosts", map[string]interface{
	"Order": "DESC",
}), date)

The templates are parsed immediately and recursively.

Namespaces

The templates can be organized in namespaces and stored in multiple root directories.

templates1/
|-- roles/
|	|-- queries.sql
|-- users/
|	|-- queries.sql
|	|-- commands.sql

templates2/
|-- posts/
|	|-- queries.sql
|	|-- commands.sql
|-- users/
|	|-- queries.sql
|-- queries.sql

The blocks inside the sql files are merged, the blocks with the same namespace and name will be overridden following the alphabetical order.

The sub-directories are used as namespaces and accessed like:

gqt.Add("../templates1", "*.sql")
gqt.Add("../templates2", "*.sql")

// Will search inside templates1/users/*.sql and templates2/users/*.sql
gqt.Get("users/allUsers")

Multiple databases

When dealing with multiple databases at the same time, like PostgreSQL and MySQL, just create two repositories:

// Use a common directory
dir := "/path/to/sql/repository/dir"

// Create the PostgreSQL repository
pgsql := gqt.NewRepository()
pgsql.Add(dir, "*.pg.sql")

// Create a separated MySQL repository
mysql := gqt.NewRepository()
mysql.Add(dir, "*.my.sql")

// Then execute
pgsql.Get("queryName")
mysql.Get("queryName")

License

Use of this source code is governed by a BSD-style license that can be found in the LICENSE file.

Davmuz / gqt