sql = "CONSTRAINT ? FOREIGN KEY ? REFERENCES ??"
	if constraint.OnDelete != "" {
		sql += " ON DELETE " + constraint.OnDelete
	}

	if constraint.OnUpdate != "" {
		sql += " ON UPDATE " + constraint.OnUpdate
	}

	foreignKeys := make([]interface{}, 0, len(constraint.ForeignKeys))
	for _, field := range constraint.ForeignKeys {
		foreignKeys = append(foreignKeys, clause.Column{Name: field.DBName})

						if rel.Field.IgnoreMigration {
							continue
						}
						if constraint := rel.ParseConstraint(); constraint != nil &&
							constraint.Schema == stmt.Schema && !queryTx.Migrator().HasConstraint(value, constraint.Name) {
							if err := execTx.Migrator().CreateConstraint(value, constraint.Name); err != nil {
								return err
							}
						}
					}
				}

        <constraint name="__context__" within="" contains="" />
        <constraint name="TYPE" within="" contains="" />
        <constraint name="ARR" nameOfExprType=".*\[\]" within="" contains="" />
        <constraint name="RES" nameOfExprType="boolean" exprTypeWithinHierarchy="true" within="" contains="" />
        <constraint name="ITEM" within="" contains="" />
        <constraint name="TARGET" within="" contains="" />

		}

		constraints := user.ParseUniqueConstraints()
		if len(constraints) != 1 {
			t.Fatalf("failed to find unique constraint, got %v", constraints)
		}

		for key := range constraints {
			if len(key) != 63 {
				t.Errorf("failed to find unique constraint, got %v", constraints)
			}
		}
	})

	t.Run("naming strategy", func(t *testing.T) {

	}

	if name := DB.Dialector.Name(); name == "postgres" {
		t.Skip("skip postgres due to it only allow unique constraint matching given keys")
	}
	if name := DB.Dialector.Name(); name == "gaussdb" {
		t.Skip("skip gaussdb due to it only allow unique constraint matching given keys")
	}

	DB.Migrator().DropTable(&Blog{}, &Tag{}, "blog_tags", "locale_blog_tags", "shared_blog_tags")

	replaceDirective = "REPLACE"
	accessDirective  = "ACCESS"
)

// Parses location constraint from the incoming reader.
func parseLocationConstraint(r *http.Request) (location string, s3Error APIErrorCode) {
	// If the request has no body with content-length set to 0,
	// we do not have to validate location constraint. Bucket will
	// be created at default region.
	locationConstraint := createBucketLocationConfiguration{}

	}

	expectedConstraintName := "fk_my_schema_a_very_very_very_very_very_very_very_very_l4db13eec"
	constraint := s.Relationships.Relations["Author"].ParseConstraint()

	if constraint.Name != expectedConstraintName {
		t.Fatalf(
			"expected constraint name %s, got %s",
			expectedConstraintName,
			constraint.Name,
		)
	}
}

type InfoRelation struct {
	ID    int
	Code  string

	GlobalStaleUploadsCleanupInterval = time.Hour * 6 // 6 hrs.

	// Refresh interval to update in-memory iam config cache.
	globalRefreshIAMInterval = 10 * time.Minute

	// Limit of location constraint XML for unauthenticated PUT bucket operations.
	maxLocationConstraintSize = 3 * humanize.MiByte

	// Maximum size of default bucket encryption configuration allowed
	maxBucketSSEConfigSize = 1 * humanize.MiByte

pkg go/types, method (*Term) Tilde() bool
pkg go/types, method (*Term) Type() Type
pkg go/types, method (*TypeList) At(int) Type
pkg go/types, method (*TypeList) Len() int
pkg go/types, method (*TypeParam) Constraint() Type
pkg go/types, method (*TypeParam) Index() int
pkg go/types, method (*TypeParam) Obj() *TypeName
pkg go/types, method (*TypeParam) SetConstraint(Type)
pkg go/types, method (*TypeParam) String() string

    cache.put(2, 20);
    cache.put(3, 30);
    cache.put(4, 40);
    cache.put(5, 50);

    assertThat(cache.getIfPresent(10)).isNull();
    // Order required to remove dependence on access order / write order constraint.
    assertThat(cache.getIfPresent(2)).isEqualTo(20);
    assertThat(cache.getIfPresent(3)).isEqualTo(30);
    assertThat(cache.getIfPresent(4)).isEqualTo(40);
    assertThat(cache.getIfPresent(5)).isEqualTo(50);