Exemplo n.º 1
0
func (r *Router) generateSelectSql(plan *Plan, stmt sqlparser.Statement) error {
	sqls := make(map[string][]string)
	node, ok := stmt.(*sqlparser.Select)
	if ok == false {
		return errors.ErrStmtConvert
	}
	if len(plan.RouteNodeIndexs) == 0 {
		return errors.ErrNoRouteNode
	}
	if len(plan.RouteTableIndexs) == 0 {
		buf := sqlparser.NewTrackedBuffer(nil)
		stmt.Format(buf)
		nodeName := r.Nodes[0]
		sqls[nodeName] = []string{buf.String()}
	} else {
		tableCount := len(plan.RouteTableIndexs)
		for i := 0; i < tableCount; i++ {
			tableIndex := plan.RouteTableIndexs[i]
			nodeIndex := plan.Rule.TableToNode[tableIndex]
			nodeName := r.Nodes[nodeIndex]
			selectSql := r.rewriteSelectSql(plan, node, tableIndex)
			if _, ok := sqls[nodeName]; ok == false {
				sqls[nodeName] = make([]string, 0, tableCount)
			}
			sqls[nodeName] = append(sqls[nodeName], selectSql)
		}
	}
	plan.RewrittenSqls = sqls
	return nil
}
Exemplo n.º 2
0
func (r *Router) generateReplaceSql(plan *Plan, stmt sqlparser.Statement) error {
	sqls := make(map[string][]string)
	node, ok := stmt.(*sqlparser.Replace)
	if ok == false {
		return errors.ErrStmtConvert
	}
	if len(plan.RouteNodeIndexs) == 0 {
		return errors.ErrNoRouteNode
	}
	if len(plan.RouteTableIndexs) == 0 {
		buf := sqlparser.NewTrackedBuffer(nil)
		stmt.Format(buf)
		nodeName := r.Nodes[0]
		sqls[nodeName] = []string{buf.String()}
	} else {
		tableCount := len(plan.RouteTableIndexs)
		for i := 0; i < tableCount; i++ {
			tableIndex := plan.RouteTableIndexs[i]
			nodeIndex := plan.Rule.TableToNode[tableIndex]
			nodeName := r.Nodes[nodeIndex]

			buf := sqlparser.NewTrackedBuffer(nil)
			buf.Fprintf("replace %vinto %v",
				node.Comments,
				node.Table,
			)
			fmt.Fprintf(buf, "_%04d", plan.RouteTableIndexs[i])
			buf.Fprintf("%v %v",
				node.Columns,
				plan.Rows[tableIndex],
			)

			if _, ok := sqls[nodeName]; ok == false {
				sqls[nodeName] = make([]string, 0, tableCount)
			}
			sqls[nodeName] = append(sqls[nodeName], buf.String())
		}

	}
	plan.RewrittenSqls = sqls
	return nil
}
Exemplo n.º 3
0
//rewrite select sql
func (r *Router) rewriteSelectSql(plan *Plan, node *sqlparser.Select, tableIndex int) string {
	buf := sqlparser.NewTrackedBuffer(nil)
	buf.Fprintf("select %v%s%v",
		node.Comments,
		node.Distinct,
		node.SelectExprs,
	)
	//insert the group columns in the first of select cloumns
	if len(node.GroupBy) != 0 {
		prefix := ","
		for _, n := range node.GroupBy {
			buf.Fprintf("%s%v", prefix, n)
		}
	}
	buf.Fprintf(" from ")
	switch v := (node.From[0]).(type) {
	case *sqlparser.AliasedTableExpr:
		if len(v.As) != 0 {
			fmt.Fprintf(buf, "%s_%04d as %s",
				sqlparser.String(v.Expr),
				tableIndex,
				string(v.As),
			)
		} else {
			fmt.Fprintf(buf, "%s_%04d",
				sqlparser.String(v.Expr),
				tableIndex,
			)
		}
	case *sqlparser.JoinTableExpr:
		if ate, ok := (v.LeftExpr).(*sqlparser.AliasedTableExpr); ok {
			if len(ate.As) != 0 {
				fmt.Fprintf(buf, "%s_%04d as %s",
					sqlparser.String(ate.Expr),
					tableIndex,
					string(ate.As),
				)
			} else {
				fmt.Fprintf(buf, "%s_%04d",
					sqlparser.String(ate.Expr),
					tableIndex,
				)
			}
		} else {
			fmt.Fprintf(buf, "%s_%04d",
				sqlparser.String(v.LeftExpr),
				tableIndex,
			)
		}
		buf.Fprintf(" %s %v", v.Join, v.RightExpr)
		if v.On != nil {
			buf.Fprintf(" on %v", v.On)
		}
	default:
		fmt.Fprintf(buf, "%s_%04d",
			sqlparser.String(node.From[0]),
			tableIndex,
		)
	}
	//append other tables
	prefix := ", "
	for i := 1; i < len(node.From); i++ {
		buf.Fprintf("%s%v", prefix, node.From[i])
	}
	buf.Fprintf("%v%v%v%v%s",
		node.Where,
		node.GroupBy,
		node.Having,
		node.OrderBy,
		node.Lock,
	)
	return buf.String()
}