orm add sqlite3 support, may be support postgres in next commit

orm/db_postgres.go

@@ -1,9 +1,66 @@
 package orm
 
+import (
+	"strconv"
+)
+
+var postgresOperators = map[string]string{
+	"exact":       "= ?",
+	"iexact":      "= UPPER(?)",
+	"contains":    "LIKE ?",
+	"icontains":   "LIKE UPPER(?)",
+	"gt":          "> ?",
+	"gte":         ">= ?",
+	"lt":          "< ?",
+	"lte":         "<= ?",
+	"startswith":  "LIKE ?",
+	"endswith":    "LIKE ?",
+	"istartswith": "LIKE UPPER(?)",
+	"iendswith":   "LIKE UPPER(?)",
+}
+
 type dbBasePostgres struct {
 	dbBase
 }
 
+var _ dbBaser = new(dbBasePostgres)
+
+func (d *dbBasePostgres) OperatorSql(operator string) string {
+	return postgresOperators[operator]
+}
+
+func (d *dbBasePostgres) TableQuote() string {
+	return `"`
+}
+
+func (d *dbBasePostgres) ReplaceMarks(query *string) {
+	q := *query
+	num := 0
+	for _, c := range q {
+		if c == '?' {
+			num += 1
+		}
+	}
+	if num == 0 {
+		return
+	}
+	data := make([]byte, 0, len(q)+num)
+	num = 1
+	for i := 0; i < len(q); i++ {
+		c := q[i]
+		if c == '?' {
+			data = append(data, '$')
+			data = append(data, []byte(strconv.Itoa(num))...)
+			num += 1
+		} else {
+			data = append(data, c)
+		}
+	}
+	*query = string(data)
+}
+
+// func (d *dbBasePostgres)
+
 func newdbBasePostgres() dbBaser {
 	b := new(dbBasePostgres)
 	b.ins = b