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core/filter.go
2014-04-11 23:32:10 +08:00

65 lines
1.5 KiB
Go

package core
import (
"fmt"
"strings"
)
// Filter is an interface to filter SQL
type Filter interface {
Do(sql string, dialect Dialect, table *Table) string
}
// QuoteFilter filter SQL replace ` to database's own quote character
type QuoteFilter struct {
}
func (s *QuoteFilter) Do(sql string, dialect Dialect, table *Table) string {
return strings.Replace(sql, "`", dialect.QuoteStr(), -1)
}
// IdFilter filter SQL replace (id) to primary key column name
type IdFilter struct {
}
type Quoter struct {
dialect Dialect
}
func NewQuoter(dialect Dialect) *Quoter {
return &Quoter{dialect}
}
func (q *Quoter) Quote(content string) string {
return q.dialect.QuoteStr() + content + q.dialect.QuoteStr()
}
func (i *IdFilter) Do(sql string, dialect Dialect, table *Table) string {
quoter := NewQuoter(dialect)
if table != nil && len(table.PrimaryKeys) == 1 {
sql = strings.Replace(sql, "`(id)`", quoter.Quote(table.PrimaryKeys[0]), -1)
sql = strings.Replace(sql, quoter.Quote("(id)"), quoter.Quote(table.PrimaryKeys[0]), -1)
return strings.Replace(sql, "(id)", quoter.Quote(table.PrimaryKeys[0]), -1)
}
return sql
}
// SeqFilter filter SQL replace ?, ? ... to $1, $2 ...
type SeqFilter struct {
Prefix string
Start int
}
func (s *SeqFilter) Do(sql string, dialect Dialect, table *Table) string {
segs := strings.Split(sql, "?")
size := len(segs)
res := ""
for i, c := range segs {
if i < size-1 {
res += c + fmt.Sprintf("%s%v", s.Prefix, i+s.Start)
}
}
res += segs[size-1]
return res
}