build_helpers.go

package qb

import (
	"strings"
)

// Values used when building queries
var (
	COMMA   = `, `
	NEWLINE = "\n"
	INDENT  = "\t"
	VALUE   = `?`
)

///// Field /////

// MakeField returns the value as a Field, no operation performed when the value is already a field.
// This function is not intended to be called directly
func MakeField(i interface{}) Field {
	switch f := i.(type) {
	case Field:
		return f
	case SelectQuery:
		return subqueryField{f}
	}

	return Value(i)
}

// ConcatQuery combines strings and Fields into string.
// This function is not intended to be called directly
func ConcatQuery(c *Context, values ...interface{}) string {
	s := strings.Builder{}

	for _, val := range values {
		switch v := val.(type) {
		case (Field):
			s.WriteString(v.QueryString(c))
		case (Condition):
			s.WriteString(v(c))
		case (SelectQuery):
			sql, _ := v.SQL(SQLBuilder{Context: c})
			s.WriteString(getSubQuerySQL(sql))
		case (string):
			s.WriteString(v)
		default:
			panic(`Can only use strings, Fields, Conditions and SelectQueries to build SQL`)
		}
	}
	return s.String()
}

// JoinQuery joins fields or values into a string separated by sep.
// This function is not intended to be called directly
func JoinQuery(c *Context, sep string, values []interface{}) string {
	s := make([]interface{}, len(values)*2-1)
	for k, v := range values {
		if k > 0 {
			s[k*2-1] = sep
		}
		s[k*2] = MakeField(v)
	}

	return ConcatQuery(c, s...)
}