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generator.go
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generator.go
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package clause
import (
"fmt"
"strings"
)
type generator func(values ...interface{}) (string, []interface{})
var generators map[Type]generator
func init() {
generators = make(map[Type]generator)
generators[INSERT] = _insert
generators[VALUES] = _values
generators[SELECT] = _select
generators[LIMIT] = _limit
generators[WHERE] = _where
generators[ORDERBY] = _orderBy
generators[UPDATE] = _update
generators[DELETE] = _delete
generators[COUNT] = _count
}
func genBindVars(num int) string {
var vars []string
for i := 0; i < num; i++ {
vars = append(vars, "?")
}
return strings.Join(vars, ", ")
}
func _insert(values ...interface{}) (string, []interface{}) {
tableName := values[0]
fields := strings.Join(values[1].([]string), ",")
return fmt.Sprintf("INSERT INTO %s (%v)", tableName, fields), []interface{}{}
}
func _values(values ...interface{}) (string, []interface{}) {
var (
bindStr string
sql strings.Builder
vars []interface{}
)
sql.WriteString("VALUES")
for i, value := range values {
v := value.([]interface{})
if bindStr == "" {
bindStr = genBindVars(len(v))
}
sql.WriteString(fmt.Sprintf("(%v)", bindStr))
if i+1 != len(values) {
sql.WriteString(", ")
}
vars = append(vars, v...)
}
return sql.String(), vars
}
func _select(values ...interface{}) (string, []interface{}) {
tableName := values[0]
fields := strings.Join(values[1].([]string), ",")
return fmt.Sprintf("SELECT %v FROM %s", fields, tableName), []interface{}{}
}
func _limit(values ...interface{}) (string, []interface{}) {
return "LIMIT ?", values
}
func _where(values ...interface{}) (string, []interface{}) {
desc, vars := values[0], values[1:]
return fmt.Sprintf("WHERE %s", desc), vars
}
func _orderBy(values ...interface{}) (string, []interface{}) {
return fmt.Sprintf("ORDER BY %s", values[0]), []interface{}{}
}
func _count(values ...interface{}) (string, []interface{}) {
return _select(values[0], []string{"count(*)"})
}
func _delete(values ...interface{}) (string, []interface{}) {
return fmt.Sprintf("DELETE FROM %s", values[0]), []interface{}{}
}
func _update(values ...interface{}) (string, []interface{}) {
tableName := values[0]
m := values[1].(map[string]interface{})
var keys []string
var vars []interface{}
for k, v := range m {
keys = append(keys, k+" = ?")
vars = append(vars, v)
}
return fmt.Sprintf("UPDATE %s SET %s", tableName, strings.Join(keys, ", ")), vars
}