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SelectValue(s) require exactly one column

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This commit is contained in:
Jack Christensen 2013-06-29 13:39:35 -05:00
parent 3acfffc142
commit 6339e54be4
2 changed files with 29 additions and 0 deletions
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19
connection.go
View File

@ -37,6 +37,15 @@ func (e NotSingleRowError) Error() string {
return fmt.Sprintf("Expected to find 1 row exactly, instead found %d", e.RowCount) return fmt.Sprintf("Expected to find 1 row exactly, instead found %d", e.RowCount)
} }
type UnexpectedColumnCountError struct {
ExpectedCount int16
ActualCount int16
}
func (e UnexpectedColumnCountError) Error() string {
return fmt.Sprintf("Expected result to have %d column(s), instead it has %d", e.ExpectedCount, e.ActualCount)
}
func Connect(parameters ConnectionParameters) (c *Connection, err error) { func Connect(parameters ConnectionParameters) (c *Connection, err error) {
c = new(Connection) c = new(Connection)
@ -165,11 +174,16 @@ func (c *Connection) SelectRow(sql string) (row map[string]interface{}, err erro
return return
} }
// Returns a UnexpectedColumnCountError if exactly one column is not found
// Returns a NotSingleRowError if exactly one row is not found // Returns a NotSingleRowError if exactly one row is not found
func (c *Connection) SelectValue(sql string) (v interface{}, err error) { func (c *Connection) SelectValue(sql string) (v interface{}, err error) {
var numRowsFound int64 var numRowsFound int64
onDataRow := func(r *DataRowReader) error { onDataRow := func(r *DataRowReader) error {
if len(r.fields) != 1 {
return UnexpectedColumnCountError{ExpectedCount: 1, ActualCount: int16(len(r.fields))}
}
numRowsFound++ numRowsFound++
v = r.ReadValue() v = r.ReadValue()
return nil return nil
@ -183,9 +197,14 @@ func (c *Connection) SelectValue(sql string) (v interface{}, err error) {
return return
} }
// Returns a UnexpectedColumnCountError if exactly one column is not found
func (c *Connection) SelectValues(sql string) (values []interface{}, err error) { func (c *Connection) SelectValues(sql string) (values []interface{}, err error) {
values = make([]interface{}, 0, 8) values = make([]interface{}, 0, 8)
onDataRow := func(r *DataRowReader) error { onDataRow := func(r *DataRowReader) error {
if len(r.fields) != 1 {
return UnexpectedColumnCountError{ExpectedCount: 1, ActualCount: int16(len(r.fields))}
}
values = append(values, r.ReadValue()) values = append(values, r.ReadValue())
return nil return nil
} }

10
connection_test.go
View File

@ -236,6 +236,11 @@ func TestConnectionSelectValue(t *testing.T) {
if _, ok := err.(NotSingleRowError); !ok { if _, ok := err.(NotSingleRowError); !ok {
t.Error("Multiple matching rows should have returned NotSingleRowError") t.Error("Multiple matching rows should have returned NotSingleRowError")
} }
_, err = conn.SelectValue("select 'Matthew', 'Mark'")
if _, ok := err.(UnexpectedColumnCountError); !ok {
t.Error("Multiple columns should have returned UnexpectedColumnCountError")
}
} }
func TestSelectValues(t *testing.T) { func TestSelectValues(t *testing.T) {
@ -262,4 +267,9 @@ func TestSelectValues(t *testing.T) {
test("select * from (values ('Matthew'), ('Mark'), ('Luke'), ('John')) t", []interface{}{"Matthew", "Mark", "Luke", "John"}) test("select * from (values ('Matthew'), ('Mark'), ('Luke'), ('John')) t", []interface{}{"Matthew", "Mark", "Luke", "John"})
test("select * from (values ('Matthew'), (null)) t", []interface{}{"Matthew", nil}) test("select * from (values ('Matthew'), (null)) t", []interface{}{"Matthew", nil})
test("select * from (values (1::int4), (2::int4), (null), (3::int4)) t", []interface{}{int32(1), int32(2), nil, int32(3)}) test("select * from (values (1::int4), (2::int4), (null), (3::int4)) t", []interface{}{int32(1), int32(2), nil, int32(3)})
_, err := conn.SelectValues("select 'Matthew', 'Mark'")
if _, ok := err.(UnexpectedColumnCountError); !ok {
t.Error("Multiple columns should have returned UnexpectedColumnCountError")
}
} }