Documentation
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Overview ¶
Package sql provides a generic interface around SQL (or SQL-like) databases.
The sql package must be used in conjunction with a database driver. See https://golang.org/s/sqldrivers for a list of drivers.
Drivers that do not support context cancellation will not return until after the query is completed.
For usage examples, see the wiki page at https://golang.org/s/sqlwiki.
Index ¶
- func ConvertDbVersion(version string) (int, error)
- func CtxDriverQuery(ctx context.Context, queryerCtx driver.QueryerContext, queryer driver.Queryer, ...) (driver.Rows, error)
- func NamedValueToValue(nvs []driver.NamedValue) []driver.Value
- func ValueToNamedValue(vs []driver.Value) []driver.NamedValue
- type ScanRows
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func ConvertDbVersion ¶
ConvertDbVersion convert a string db version to a number.
func CtxDriverQuery ¶
func NamedValueToValue ¶
func NamedValueToValue(nvs []driver.NamedValue) []driver.Value
func ValueToNamedValue ¶
func ValueToNamedValue(vs []driver.Value) []driver.NamedValue
Types ¶
type ScanRows ¶
type ScanRows struct {
// contains filtered or unexported fields
}
ScanRows is the result of a query. Its cursor starts before the first row of the result set. Use Next to advance from row to row.
func NewScanRows ¶
func (*ScanRows) Close ¶
Close closes the ScanRows, preventing further enumeration. If Next is called and returns false and there are no further result sets, the ScanRows are closed automatically and it will suffice to check the result of Err. Close is idempotent and does not affect the result of Err.
func (*ScanRows) Err ¶
Err returns the error, if any, that was encountered during iteration. Err may be called after an explicit or implicit Close.
func (*ScanRows) Next ¶
Next prepares the next result row for reading with the Scan method. It returns true on success, or false if there is no next result row or an error happened while preparing it. Err should be consulted to distinguish between the two cases.
Every call to Scan, even the first one, must be preceded by a call to Next.
func (*ScanRows) NextResultSet ¶
NextResultSet prepares the next result set for reading. It reports whether there is further result sets, or false if there is no further result set or if there is an error advancing to it. The Err method should be consulted to distinguish between the two cases.
After calling NextResultSet, the Next method should always be called before scanning. If there are further result sets they may not have rows in the result set.
func (*ScanRows) Scan ¶
Scan copies the columns in the current row into the values pointed at by dest. The number of values in dest must be the same as the number of columns in ScanRows.
Scan converts columns read from the database into the following common Go types and special types provided by the sql package:
*string
*[]byte
*int, *int8, *int16, *int32, *int64
*uint, *uint8, *uint16, *uint32, *uint64
*bool
*float32, *float64
*interface{}
*RawBytes
*ScanRows (cursor value)
any type implementing Scanner (see Scanner docs)
In the most simple case, if the type of the value from the source column is an integer, bool or string type T and dest is of type *T, Scan simply assigns the value through the pointer.
Scan also converts between string and numeric types, as long as no information would be lost. While Scan stringifies all numbers scanned from numeric database columns into *string, scans into numeric types are checked for overflow. For example, a float64 with value 300 or a string with value "300" can scan into a uint16, but not into a uint8, though float64(255) or "255" can scan into a uint8. One exception is that scans of some float64 numbers to strings may lose information when stringifying. In general, scan floating point columns into *float64.
If a dest argument has type *[]byte, Scan saves in that argument a copy of the corresponding data. The copy is owned by the caller and can be modified and held indefinitely. The copy can be avoided by using an argument of type *RawBytes instead; see the documentation for RawBytes for restrictions on its use.
If an argument has type *interface{}, Scan copies the value provided by the underlying driver without conversion. When scanning from a source value of type []byte to *interface{}, a copy of the slice is made and the caller owns the result.
Source values of type time.Time may be scanned into values of type *time.Time, *interface{}, *string, or *[]byte. When converting to the latter two, time.RFC3339Nano is used.
Source values of type bool may be scanned into types *bool, *interface{}, *string, *[]byte, or *RawBytes.
For scanning into *bool, the source may be true, false, 1, 0, or string inputs parseable by strconv.ParseBool.
Scan can also convert a cursor returned from a query, such as "select cursor(select * from my_table) from dual", into a *ScanRows value that can itself be scanned from. The parent select query will close any cursor *ScanRows if the parent *ScanRows is closed.
If any of the first arguments implementing Scanner returns an error, that error will be wrapped in the returned error
Source Files