Method parseOnConflictClause

pkg/sql/parser/dml_insert.go:263–365

parseOnConflictClause parses the ON CONFLICT clause (PostgreSQL UPSERT) Syntax: ON CONFLICT [(columns)] | ON CONSTRAINT name DO NOTHING | DO UPDATE SET ...

()

// parseOnConflictClause parses the ON CONFLICT clause (PostgreSQL UPSERT)
// Syntax: ON CONFLICT [(columns)] | ON CONSTRAINT name DO NOTHING | DO UPDATE SET ...
func (p *Parser) parseOnConflictClause() (*ast.OnConflict, error) {
	onConflict := &ast.OnConflict{}

	// Parse optional conflict target: (column_list) or ON CONSTRAINT constraint_name
	if p.isType(models.TokenTypeLParen) {
		p.advance() // Consume (
		var targets []ast.Expression

		for {
			if !p.isIdentifier() {
				return nil, p.expectedError("column name in ON CONFLICT target")
			}
			targets = append(targets, &ast.Identifier{Name: p.currentToken.Token.Value})
			p.advance()

			if !p.isType(models.TokenTypeComma) {
				break
			}
			p.advance() // Consume comma
		}

		if !p.isType(models.TokenTypeRParen) {
			return nil, p.expectedError(")")
		}
		p.advance() // Consume )
		onConflict.Target = targets
	} else if p.isType(models.TokenTypeOn) && p.peekToken().Token.Value == "CONSTRAINT" {
		// ON CONSTRAINT constraint_name
		p.advance() // Consume ON
		p.advance() // Consume CONSTRAINT
		if !p.isIdentifier() {
			return nil, p.expectedError("constraint name")
		}
		onConflict.Constraint = p.currentToken.Token.Value
		p.advance()
	}

	// Parse DO keyword
	if p.currentToken.Token.Value != "DO" {
		return nil, p.expectedError("DO")
	}
	p.advance() // Consume DO

	// Parse action: NOTHING or UPDATE
	if p.currentToken.Token.Value == "NOTHING" {
		onConflict.Action = ast.OnConflictAction{DoNothing: true}
		p.advance() // Consume NOTHING
	} else if p.isType(models.TokenTypeUpdate) {
		p.advance() // Consume UPDATE

		// Parse SET keyword
		if !p.isType(models.TokenTypeSet) {
			return nil, p.expectedError("SET")
		}
		p.advance() // Consume SET

		// Parse update assignments
		var updates []ast.UpdateExpression