Make Drivers Simpler

driver.go

@@ -11,28 +11,30 @@ var (
 	drivers   = make(map[string]Driver)
 )
 
-// Driver interface defines the contract for database-specific implementations.
-// Each database driver handles SQL dialect differences, keyword quoting, and placeholders.
-// Functions are handled generically by the SQL builder without driver-specific translation.
-type Driver interface {
-	// Name returns the driver name (e.g., "postgres", "mysql", "clickhouse").
-	Name() string
+type (
+	// Driver interface defines the contract for database-specific implementations.
+	// Each database driver handles SQL dialect differences, keyword quoting, and placeholders.
+	// Functions are handled generically by the SQL builder without driver-specific translation.
+	Driver interface {
+		// Name returns the driver name (e.g., "postgres", "mysql", "clickhouse").
+		Name() string
 
-	// QuoteIdentifier quotes database identifiers to handle reserved keywords and special characters.
-	QuoteIdentifier(name string) string
+		// QuoteIdentifier quotes database identifiers to handle reserved keywords and special characters.
+		QuoteIdentifier(name string) string
 
-	// Placeholder returns the placeholder syntax for the given parameter position.
-	Placeholder(position int) string
+		// Placeholder returns the placeholder syntax for the given parameter position.
+		Placeholder(position int) string
 
-	// IsReservedKeyword returns true if the word is a reserved keyword in this database.
-	IsReservedKeyword(word string) bool
+		// IsReservedKeyword returns true if the word is a reserved keyword in this database.
+		IsReservedKeyword(word string) bool
 
-	// TranslateOperator translates an operator to database-specific syntax.
-	TranslateOperator(op string) (translated string, supported bool)
+		// TranslateOperator translates an operator to database-specific syntax.
+		TranslateOperator(op string) (translated string, supported bool)
 
-	// SupportsFeature returns true if the database supports the named feature.
-	SupportsFeature(feature string) bool
-}
+		// SupportsFeature returns true if the database supports the named feature.
+		SupportsFeature(feature string) bool
+	}
+)
 
 // RegisterDriver registers a database driver with the given name.
 // This function is typically called from driver package init() functions.
@@ -74,3 +76,30 @@ func ListDrivers() []string {
 	}
 	return names
 }
+
+// NeedsQuoting determines if an identifier needs to be quoted.
+// This implements the common SQL identifier quoting rules used across all database drivers.
+func NeedsQuoting(name string, driver Driver) bool {
+	if driver.IsReservedKeyword(name) {
+		return true
+	}
+
+	if name == "" {
+		return false
+	}
+
+	if name[0] >= '0' && name[0] <= '9' {
+		return true
+	}
+
+	for _, ch := range name {
+		if (ch < 'a' || ch > 'z') &&
+			(ch < 'A' || ch > 'Z') &&
+			(ch < '0' || ch > '9') &&
+			ch != '_' {
+			return true
+		}
+	}
+
+	return false
+}

drivers/clickhouse/clickhouse.go

@@ -2,16 +2,31 @@ package clickhouse
 
 import (
 	"fmt"
+	"slices"
 	"strings"
 
 	"github.com/pseudomuto/where"
 )
 
-// ClickHouseDriver implements the where.Driver interface for ClickHouse databases.
-type ClickHouseDriver struct {
-	keywords map[string]bool
+var supportsFeatures = []string{
+	"ARRAY",
+	"FINAL",
+	"GLOBAL",
+	"ILIKE",
+	"JSON",
+	"PREWHERE",
+	"SAMPLE",
+	"TUPLE",
+	"WITH",
 }
 
+type (
+	// ClickHouseDriver implements the where.Driver interface for ClickHouse databases.
+	ClickHouseDriver struct {
+		keywords map[string]bool
+	}
+)
+
 // NewClickHouseDriver creates a new ClickHouse driver instance.
 //
 // Example:
@@ -60,37 +75,12 @@ func (d *ClickHouseDriver) QuoteIdentifier(name string) string {
 }
 
 func (d *ClickHouseDriver) quoteSimpleIdentifier(name string) string {
-	if d.needsQuoting(name) {
+	if where.NeedsQuoting(name, d) {
 		return fmt.Sprintf("`%s`", strings.ReplaceAll(name, "`", "``"))
 	}
 	return name
 }
 
-func (d *ClickHouseDriver) needsQuoting(name string) bool {
-	if d.IsReservedKeyword(name) {
-		return true
-	}
-
-	if name == "" {
-		return false
-	}
-
-	if name[0] >= '0' && name[0] <= '9' {
-		return true
-	}
-
-	for _, ch := range name {
-		if (ch < 'a' || ch > 'z') &&
-			(ch < 'A' || ch > 'Z') &&
-			(ch < '0' || ch > '9') &&
-			ch != '_' {
-			return true
-		}
-	}
-
-	return false
-}
-
 func (d *ClickHouseDriver) Placeholder(position int) string {
 	return "?"
 }
@@ -118,14 +108,7 @@ func (d *ClickHouseDriver) TranslateOperator(op string) (string, bool) {
 }
 
 func (d *ClickHouseDriver) SupportsFeature(feature string) bool {
-	switch strings.ToUpper(feature) {
-	case "ILIKE", "ARRAY", "TUPLE", "WITH", "SAMPLE", "PREWHERE", "FINAL", "GLOBAL":
-		return true
-	case "JSON":
-		return true
-	default:
-		return false
-	}
+	return slices.Contains(supportsFeatures, strings.ToUpper(feature))
 }
 
 func init() {

drivers/mysql/mysql.go

@@ -2,16 +2,27 @@ package mysql
 
 import (
 	"fmt"
+	"slices"
 	"strings"
 
 	"github.com/pseudomuto/where"
 )
 
-// MySQLDriver implements the where.Driver interface for MySQL and MariaDB databases.
-type MySQLDriver struct {
-	keywords map[string]bool
+var supportedFeatures = []string{
+	"CTE",
+	"FULLTEXT",
+	"JSON",
+	"PARTITION",
+	"SPATIAL",
 }
 
+type (
+	// MySQLDriver implements the where.Driver interface for MySQL and MariaDB databases.
+	MySQLDriver struct {
+		keywords map[string]bool
+	}
+)
+
 // NewMySQLDriver creates a new MySQL driver instance.
 //
 // Example:
@@ -60,37 +71,12 @@ func (d *MySQLDriver) QuoteIdentifier(name string) string {
 }
 
 func (d *MySQLDriver) quoteSimpleIdentifier(name string) string {
-	if d.needsQuoting(name) {
+	if where.NeedsQuoting(name, d) {
 		return fmt.Sprintf("`%s`", strings.ReplaceAll(name, "`", "``"))
 	}
 	return name
 }
 
-func (d *MySQLDriver) needsQuoting(name string) bool {
-	if d.IsReservedKeyword(name) {
-		return true
-	}
-
-	if name == "" {
-		return false
-	}
-
-	if name[0] >= '0' && name[0] <= '9' {
-		return true
-	}
-
-	for _, ch := range name {
-		if (ch < 'a' || ch > 'z') &&
-			(ch < 'A' || ch > 'Z') &&
-			(ch < '0' || ch > '9') &&
-			ch != '_' {
-			return true
-		}
-	}
-
-	return false
-}
-
 func (d *MySQLDriver) Placeholder(position int) string {
 	return "?"
 }
@@ -122,14 +108,7 @@ func (d *MySQLDriver) TranslateOperator(op string) (string, bool) {
 }
 
 func (d *MySQLDriver) SupportsFeature(feature string) bool {
-	switch strings.ToUpper(feature) {
-	case "JSON", "FULLTEXT", "SPATIAL", "PARTITION", "CTE":
-		return true
-	case "ILIKE":
-		return false
-	default:
-		return false
-	}
+	return slices.Contains(supportedFeatures, strings.ToUpper(feature))
 }
 
 func init() {

drivers/postgres/postgres.go

@@ -2,16 +2,29 @@ package postgres
 
 import (
 	"fmt"
+	"slices"
 	"strings"
 
 	"github.com/pseudomuto/where"
 )
 
-// PostgreSQLDriver implements the where.Driver interface for PostgreSQL databases.
-type PostgreSQLDriver struct {
-	keywords map[string]bool
+var supportedFeatures = []string{
+	"ARRAY",
+	"CTE",
+	"ILIKE",
+	"JSON",
+	"JSONB",
+	"RETURNING",
+	"WINDOW",
 }
 
+type (
+	// PostgreSQLDriver implements the where.Driver interface for PostgreSQL databases.
+	PostgreSQLDriver struct {
+		keywords map[string]bool
+	}
+)
+
 // NewPostgreSQLDriver creates a new PostgreSQL driver instance.
 //
 // Example:
@@ -60,37 +73,12 @@ func (d *PostgreSQLDriver) QuoteIdentifier(name string) string {
 }
 
 func (d *PostgreSQLDriver) quoteSimpleIdentifier(name string) string {
-	if d.needsQuoting(name) {
+	if where.NeedsQuoting(name, d) {
 		return fmt.Sprintf(`"%s"`, strings.ReplaceAll(name, `"`, `""`))
 	}
 	return name
 }
 
-func (d *PostgreSQLDriver) needsQuoting(name string) bool {
-	if d.IsReservedKeyword(name) {
-		return true
-	}
-
-	if name == "" {
-		return false
-	}
-
-	if name[0] >= '0' && name[0] <= '9' {
-		return true
-	}
-
-	for _, ch := range name {
-		if (ch < 'a' || ch > 'z') &&
-			(ch < 'A' || ch > 'Z') &&
-			(ch < '0' || ch > '9') &&
-			ch != '_' {
-			return true
-		}
-	}
-
-	return false
-}
-
 func (d *PostgreSQLDriver) Placeholder(position int) string {
 	return fmt.Sprintf("$%d", position)
 }
@@ -118,12 +106,7 @@ func (d *PostgreSQLDriver) TranslateOperator(op string) (string, bool) {
 }
 
 func (d *PostgreSQLDriver) SupportsFeature(feature string) bool {
-	switch strings.ToUpper(feature) {
-	case "ILIKE", "ARRAY", "JSON", "JSONB", "RETURNING", "CTE", "WINDOW":
-		return true
-	default:
-		return false
-	}
+	return slices.Contains(supportedFeatures, strings.ToUpper(feature))
 }
 
 func init() {