github.com/cockroachdb/cockroachdb-parser@v0.23.3-0.20240213214944-911057d40c9a/pkg/sql/sem/tree/comment_on_constraint.go (about)

     1  // Copyright 2018 The Cockroach Authors.
     2  //
     3  // Use of this software is governed by the Business Source License
     4  // included in the file licenses/BSL.txt.
     5  //
     6  // As of the Change Date specified in that file, in accordance with
     7  // the Business Source License, use of this software will be governed
     8  // by the Apache License, Version 2.0, included in the file
     9  // licenses/APL.txt.
    10  
    11  package tree
    12  
    13  import "github.com/cockroachdb/cockroachdb-parser/pkg/sql/lexbase"
    14  
    15  // CommentOnConstraint represents a COMMENT ON CONSTRAINT statement
    16  type CommentOnConstraint struct {
    17  	Constraint Name
    18  	Table      *UnresolvedObjectName
    19  	Comment    *string
    20  }
    21  
    22  // Format implements the NodeFormatter interface.
    23  func (n *CommentOnConstraint) Format(ctx *FmtCtx) {
    24  	ctx.WriteString("COMMENT ON CONSTRAINT ")
    25  	ctx.FormatNode(&n.Constraint)
    26  	ctx.WriteString(" ON ")
    27  	ctx.FormatNode(n.Table)
    28  	ctx.WriteString(" IS ")
    29  	if n.Comment != nil {
    30  		// TODO(knz): Replace all this with ctx.FormatNode
    31  		// when COMMENT supports expressions.
    32  		if ctx.flags.HasFlags(FmtHideConstants) {
    33  			ctx.WriteByte('_')
    34  		} else {
    35  			lexbase.EncodeSQLStringWithFlags(&ctx.Buffer, *n.Comment, ctx.flags.EncodeFlags())
    36  		}
    37  	} else {
    38  		ctx.WriteString("NULL")
    39  	}
    40  }