sqlfunc - Stronger typing for database/sql prepared statements

sqlfunc is a Go library that simplifies the use of database/sql by binding SQL queries directly to strongly-typed Go functions. By leveraging Go generics and reflection, it provides an idiomatic and type-safe API that reduces boilerplate and minimizes common errors like incorrect column scanning or argument count mismatches.

Key Features

• Strongly-Typed Query Binding: Bind INSERT, UPDATE, DELETE, and SELECT statements directly to Go function variables. The function signature defines the SQL parameters and the expected result types.
• Exec, QueryRow, and Query: Dedicated functions for different SQL operations, ensuring that the bound functions return the appropriate results (sql.Result, individual columns, or *sql.Rows).
• ForEach Iteration: A high-level helper for iterating over *sql.Rows that automatically scans columns into the arguments of a provided callback function.
• Flexible Scan Functions: Generate reusable functions to scan a single row into pointers or return values, improving readability and reuse.
• Transaction Support: Generated functions can optionally accept a *sql.Tx as an argument, allowing them to participate seamlessly in transactions.
• Any API: Provides a more flexible, reflection-heavy API for use cases where function signatures are determined at runtime.
• Performance-Oriented Registry: Includes a registry system to cache reflective implementations, designed with future code generation in mind to achieve performance comparable to manual database/sql code.

Example: Binding a Query to a Function

import (
    "context"
    "database/sql"
    "github.com/dolmen-go/sqlfunc"
)

// Define a function variable with the desired signature
var getPOI func(ctx context.Context, name string) (lat float64, lon float64, err error)

// Bind the SQL query to the function variable
closeStmt, err := sqlfunc.QueryRow(ctx, db,
    "SELECT lat, lon FROM poi WHERE name = ?",
    &getPOI,
)
if err != nil {
    // handle error
}
defer closeStmt()

// Execute the query using the strongly-typed function
lat, lon, err := getPOI(ctx, "Château de Versailles")

Example: Using ForEach for Iteration

rows, err := db.QueryContext(ctx, "SELECT name, lat, lon FROM poi")
if err != nil { /* ... */ }

// Scan rows directly into callback arguments
err = sqlfunc.ForEach(rows, func(name string, lat, lon float64) {
    fmt.Printf("%s: %.4f, %.4f\n", name, lat, lon)
})

Documentation

• Package sqlfunc
• sqlfunc.ForEach
• sqlfunc.Query
• sqlfunc.QueryRow
• sqlfunc.Exec
• sqlfunc.Scan
• sqlfunc.Any.ForEach
• sqlfunc.Any.Query
• sqlfunc.Any.QueryRow
• sqlfunc.Any.Exec
• sqlfunc.Any.Scan

Status

Production ready.

Check code coverage by the testsuite.

Known issues

• There is a speed/memory penalty in using the sqlfunc wrappers (check go test -bench B -benchmem github.com/dolmen-go/sqlfunc). It is recommended to do your own benchmarks. However there is work in progress to add a code generator to reduce cost of runtime reflect. Check the experiment-gen branch.

Quality reports

See quality reports on SonarQube.

License

Copyright 2026 Olivier Mengué

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.