gocctl model v20200819 (#18)

* rename snake、came method

* new: generate model from data source

* add change log md

* update model doc

* update  doc

* beauty code

tools/goctl/model/sql/model/ddlmodel.go

@@ -0,0 +1,33 @@
+package model
+
+import (
+	"github.com/tal-tech/go-zero/core/stores/sqlx"
+)
+
+type (
+	DDLModel struct {
+		conn sqlx.SqlConn
+	}
+	DDL struct {
+		Table string `db:"Table"`
+		DDL   string `db:"Create Table"`
+	}
+)
+
+func NewDDLModel(conn sqlx.SqlConn) *DDLModel {
+	return &DDLModel{conn: conn}
+}
+
+func (m *DDLModel) ShowDDL(table ...string) ([]string, error) {
+	var ddl []string
+	for _, t := range table {
+		query := `show create table ` + t
+		var resp DDL
+		err := m.conn.QueryRow(&resp, query)
+		if err != nil {
+			return nil, err
+		}
+		ddl = append(ddl, resp.DDL)
+	}
+	return ddl, nil
+}