Go

sqltgen generates Go code using the standard database/sql package. Functions take a context.Context and a *sql.DB and return idiomatic (T, error) pairs.

Configuration

"go": {
  "out": "db",
  "package": "db"
}

What is generated

db/
  mod.go          — package declaration
  author.go       — Author struct
  book.go         — Book struct
  sqltgen.go      — shared helpers (execRows, buildInClause, scanArray)
  queries.go      — query functions

Model structs

// db/author.go
package db

import "database/sql"

// Author represents a row from the author table.
type Author struct {
    Id        int64
    Name      string
    Bio       sql.NullString
    BirthYear sql.NullInt32
}

• Non-null columns use bare Go types (int64, string, bool, …).
• Nullable columns use sql.Null* types (sql.NullString, sql.NullInt32, sql.NullInt64, sql.NullFloat64, sql.NullBool, sql.NullTime).
• Field names are PascalCase (e.g. birth_year → BirthYear).

Query functions

// db/queries.go
package db

import (
    "context"
    "database/sql"
)

// GetAuthor executes the GetAuthor query.
func GetAuthor(ctx context.Context, db *sql.DB, id int64) (*Author, error) {
    row := db.QueryRowContext(ctx, SQL_GET_AUTHOR, id)
    var r Author
    err := row.Scan(&r.Id, &r.Name, &r.Bio, &r.BirthYear)
    if err == sql.ErrNoRows {
        return nil, nil
    }
    if err != nil {
        return nil, err
    }
    return &r, nil
}

// ListAuthors executes the ListAuthors query.
func ListAuthors(ctx context.Context, db *sql.DB) ([]Author, error) {
    rows, err := db.QueryContext(ctx, SQL_LIST_AUTHORS)
    if err != nil {
        return nil, err
    }
    defer rows.Close()
    var results []Author
    for rows.Next() {
        var r Author
        if err := rows.Scan(&r.Id, &r.Name, &r.Bio, &r.BirthYear); err != nil {
            return nil, err
        }
        results = append(results, r)
    }
    return results, rows.Err()
}

// DeleteAuthor executes the DeleteAuthor query.
func DeleteAuthor(ctx context.Context, db *sql.DB, id int64) error {
    _, err := db.ExecContext(ctx, SQL_DELETE_AUTHOR, id)
    return err
}

// CountAuthors executes the CountAuthors query.
func CountAuthors(ctx context.Context, db *sql.DB) (int64, error) {
    // :execrows — returns affected row count
}

Return types by command:

Wiring up

go.mod

go get github.com/lib/pq          # PostgreSQL
go get modernc.org/sqlite          # SQLite (pure Go, no CGo)
go get github.com/go-sql-driver/mysql  # MySQL

PostgreSQL

import (
    "context"
    "database/sql"
    _ "github.com/lib/pq"
    "yourmodule/db"
)

conn, err := sql.Open("postgres", "postgres://user:pass@localhost/mydb?sslmode=disable")

author, err := db.GetAuthor(context.Background(), conn, 1)
all, err    := db.ListAuthors(context.Background(), conn)

SQLite

import (
    "context"
    "database/sql"
    _ "modernc.org/sqlite"
    "yourmodule/db"
)

conn, err := sql.Open("sqlite", "mydb.db")

author, err := db.GetAuthor(context.Background(), conn, 1)

MySQL

import (
    "context"
    "database/sql"
    _ "github.com/go-sql-driver/mysql"
    "yourmodule/db"
)

conn, err := sql.Open("mysql", "user:pass@tcp(localhost:3306)/mydb")

author, err := db.GetAuthor(context.Background(), conn, 1)

Inline row types

type ListBooksWithAuthorRow struct {
    Id         int64
    Title      string
    Genre      string
    Price      float64
    AuthorName string
    AuthorBio  sql.NullString
}

func ListBooksWithAuthor(ctx context.Context, db *sql.DB) ([]ListBooksWithAuthorRow, error) { … }

List parameters

For SQLite and MySQL the native strategy serializes the list to a JSON string and uses json_each / JSON_TABLE. For PostgreSQL it uses pq.Array:

// SQLite / MySQL
func GetBooksByIds(ctx context.Context, db *sql.DB, ids []int64) ([]Book, error) {
    idsJSON, _ := json.Marshal(ids)
    rows, err := db.QueryContext(ctx, SQL_GET_BOOKS_BY_IDS, string(idsJSON))
    …
}

// PostgreSQL
import "github.com/lib/pq"

func GetBooksByIds(ctx context.Context, db *sql.DB, ids []int64) ([]Book, error) {
    rows, err := db.QueryContext(ctx, SQL_GET_BOOKS_BY_IDS, pq.Array(ids))
    …
}

Naming conventions