README
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SQLT - sql/template
A lean experimental library for rendering SQL from embedded text/template files that supports ? or $1...$N parameterized placeholders, and scans results into structs or slices of structs.
See cmd/example/main.go for a functional CRUD+ api example.
EXAMPLE
Given a sql/template ...
{{ define "user/list" -}}
-- SELECT
{{ with .Select -}} select {{ . }} {{ else -}} select * {{ end }}
-- FROM
from "iam"."user"
-- WHERE
{{ with .Where -}} where {{ . }} {{ end }}
-- LIMIT
{{ with .Limit -}}
{{ if and (gt . 0) (lt . 50) -}} limit {{ . }} {{ else -}} limit 50 {{ end }}
{{- end }}
{{- end }}
... and some input data ...
userListInput := UserListInput{
Where: "city in (:cities) and age > :age",
Limit: 10,
Age: 98,
Cities: []string{"Tampa", "São Paulo", "Rio de Janeiro"},
}
... we should generate the following SQL ...
-- SELECT
select *
-- FROM
from "iam"."user"
-- WHERE
where city in ($1, $2, $3) and age > $4
-- LIMIT
limit 10
... where the encoded placeholder parameters equal the following ...
$1 = 'Tampa'
$2 = 'São Paulo'
$3 = 'Rio de Janeiro'
$4 = 98
... and are easily scanned into in-memory structures, or iterated for large per row jobs.
//go:embed sql/**/*
var templates embed.FS
// name of our template to render.
templateName := "user/list"
// input data to execute against our template.
userListInput := UserListQuery{
Where: "city in (:cities) and age > :age",
Limit: 10,
Age: 98,
Cities: []string{"Tampa", "São Paulo", "Rio de Janeiro"},
}
// users slice to scan rows into.
users := []User{}
err := api.lib.Query(ctx, templateName, &users, sqlt.Input(userListQuery))
SQLT is comprised of 5 lightweight methods named similarly to Go's standard templating & sql library names, Exec ExecuteTemplate Iterate Query QueryRow
We use embed.FS to load templates, standard go text/template for parsing templates, and sqlx to interface with databases.
type SQLT interface {
Exec(ctx context.Context, name string, opts ...QueryOption) (sql.Result, error)
ExecuteTemplate(name string, data interface{}) (string, []any, error)
Iterate(ctx context.Context, name string, iter Iterator, opts ...QueryOption) error
Query(ctx context.Context, name string, dest any, opts ...QueryOption) error
QueryRow(ctx context.Context, name string, dest any, opts ...QueryOption) error
}
Inspired by: github.com/Davmuz/gqt
Documentation
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Index ¶
Constants ¶
This section is empty.
Variables ¶
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Functions ¶
This section is empty.
Types ¶
type QueryOption ¶
type QueryOption func(*queryoptions)
QueryOption
func Input ¶
func Input(input any) QueryOption
Input is a QueryOption that sets the input data to be used when executing the template. Named bindvars (example: :my_field_name) in the sql template will be replaced with database specific placeholders (? or $1..$N) mapped to the asscociated input field-value (example: data.MyFieldName) to be sent as encoded parameters.
type SQLT ¶
type SQLT interface {
Exec(ctx context.Context, name string, opts ...QueryOption) (sql.Result, error)
ExecuteTemplate(name string, data interface{}) (string, []any, error)
Iterate(ctx context.Context, name string, iter Iterator, opts ...QueryOption) error
Query(ctx context.Context, name string, dest any, opts ...QueryOption) error
QueryRow(ctx context.Context, name string, dest any, opts ...QueryOption) error
}
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