SQL Template library

A simple template engine for writing dynamic SQL queries.

Sometimes it can be hard to write comprehensible SQL queries with tools like SQL builders (squirrel or dbr), specially dynamic queries with optional statements and joins. It can be hard to see the overall cohesive structure of the queries, and the primary goal.

The main motivation of this library is to separate the SQL queries from the Go code, and to improve the readability of complex dynamic queries.

Check out the API Documentation http://godoc.org/github.com/NicklasWallgren/sqlTemplate

Installation

The library can be installed through go get

go get github.com/NicklasWallgren/sqlTemplate

Supported versions

We support the latest major Go version, which are 1.19 at the moment.

Features and benefits

Separates SQL and Go code.
Keeps the templated query as close as possible to the actual SQL query.
Extensible template language with support for https://github.com/Masterminds/sprig
No third party dependencies
Support for embedded filesystem

API

// Parse parses a sql template and returns the 'QueryTemplate'
Parse(namespace string, templateName string) (QueryTemplate, error)

// ParseWithValuesFromMap parses a sql template with values from a map and returns the 'QueryTemplate'
ParseWithValuesFromMap(namespace string, templateName string, parameters map[string]interface{}) (QueryTemplate, error)

// ParseWithValuesFromStruct parses a sql template with values from a struct and returns the 'QueryTemplate'
ParseWithValuesFromStruct(namespace string, templateName string, parameters interface{}) (QueryTemplate, error)

// Register registers a new namespace by template filesystem and extension
Register(namespace string, filesystem fs.FS, extensions string) error

Examples

Register a namespace and parse a template

//go:embed queries/users/*.tsql
var fs embed.FS

sqlt := sqlTemplate.NewQueryTemplateEngine()
sqlt.Register("users", fs, ".tsql");

criteria := map[string]interface{}{"Name": "Bill", "Order": "id"}
tmpl, _ := sqlt.ParseWithValuesFromMap("users", "findByName", criteria)

sql.QueryRowContext(context.Background(), tmpl.GetQuery(), tmpl.GetParams())

fmt.Printf("query %v\n", tmpl.GetQuery())
fmt.Printf("query parameters %v\n", tmpl.GetParams())

-- File ./queries/users/users.tsql
{{define "findByName"}}
    SELECT *
    FROM users
    WHERE name={{bind .Name}}
    {{if .Order}}ORDER BY {{.Order}}{{end}}
{{end}}

Unit tests

go test -v -race ./pkg

For benchmark :

go test ./pkg -bench=.

Code Guide

We use GitHub Actions to make sure the codebase is consistent (golangci-lint run) and continuously tested (go test -v -race ./pkg). We try to keep comments at a maximum of 120 characters of length and code at 120.

Contributing

If you find any problems or have suggestions about this library, please submit an issue. Moreover, any pull request, code review and feedback are welcome.

Contributors

License

MIT