advsql/create_table.go

package advsql

import (
	"log"
	"reflect"
	"strings"
)

func (s *Store) createTable(structure *structure) error {
	b := new(strings.Builder)
	b.WriteString("CREATE TABLE ")
	b.WriteString(structure.TypeName)
	b.WriteString("(")

	fieldAmount := len(structure.Fields)

	for i, field := range structure.Fields {
		b.WriteString(field.FieldName)
		b.WriteString(" ")
		b.WriteString(getTypeSpecForDB(field.FieldType))

		if i < fieldAmount-1 {
			b.WriteString(",")
		}
	}

	b.WriteString(")")

	log.Println("sql command: " + b.String())

	_, err := s.db.Exec(b.String())
	if err != nil {
		return err
	}

	return nil
}

func getTypeSpecForDB(t reflect.Type) string {
	noPtrType := t
	dereferenced := false

	// derefence all pointers recursively
	for noPtrType.Kind() == reflect.Ptr {
		noPtrType = t.Elem()
		dereferenced = true
	}

	// actual data types
	b := new(strings.Builder)
	switch noPtrType.Kind() {
	case reflect.Bool:
		b.WriteString("INT")

	case reflect.Int:
		b.WriteString("BIGINT")
	case reflect.Int8:
		b.WriteString("TINYINT")
	case reflect.Int16:
		b.WriteString("SMALLINT")
	case reflect.Int32:
		b.WriteString("INT")
	case reflect.Int64:
		b.WriteString("BIGINT")

	case reflect.Uint:
		b.WriteString("BIGINT UNSIGNED")
	case reflect.Uint8:
		b.WriteString("TINYINT UNSIGNED")
	case reflect.Uint16:
		b.WriteString("SMALLINT UNSIGNED")
	case reflect.Uint32:
		b.WriteString("INT UNSIGNED")
	case reflect.Uint64:
		b.WriteString("BIGINT UNSIGNED")

	case reflect.Float32:
		b.WriteString("FLOAT")
	case reflect.Float64:
		b.WriteString("DOUBLE")

	case reflect.String:
		b.WriteString("TEXT")

	case reflect.Ptr:
		panic("something's broken. All pointers should have been dereferenced by now")
	default:
		panic("type spec for db not implemented yet: " + noPtrType.Kind().String())
	}

	if !dereferenced {
		b.WriteString(" NOT NULL")
	}

	return b.String()
}