Documentation
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Overview ¶
Package driver defines interfaces to be implemented by database drivers as used by package sql.
Most code should use package sql.
Index ¶
Constants ¶
This section is empty.
Variables ¶
var Bool boolType
Bool is a ValueConverter that converts input values to bools.
The conversion rules are:
- booleans are returned unchanged
- for integer types, 1 is true 0 is false, other integers are an error
- for strings and []byte, same rules as strconv.ParseBool
- all other types are an error
var DefaultParameterConverter defaultConverter
DefaultParameterConverter is the default implementation of ValueConverter that's used when a Stmt doesn't implement ColumnConverter.
DefaultParameterConverter returns the given value directly if IsValue(value). Otherwise integer type are converted to int64, floats to float64, and strings to []byte. Other types are an error.
var ErrBadConn = errors.New("driver: bad connection")
ErrBadConn should be returned by a driver to signal to the sql package that a driver.Conn is in a bad state (such as the server having earlier closed the connection) and the sql package should retry on a new connection.
To prevent duplicate operations, ErrBadConn should NOT be returned if there's a possibility that the database server might have performed the operation. Even if the server sends back an error, you shouldn't return ErrBadConn.
var ErrSkip = errors.New("driver: skip fast-path; continue as if unimplemented")
ErrSkip may be returned by some optional interfaces' methods to indicate at runtime that the fast path is unavailable and the sql package should continue as if the optional interface was not implemented. ErrSkip is only supported where explicitly documented.
var Int32 int32Type
Int32 is a ValueConverter that converts input values to int64, respecting the limits of an int32 value.
var ResultNoRows noRows
ResultNoRows is a pre-defined Result for drivers to return when a DDL command (such as a CREATE TABLE) succeeds. It returns an error for both LastInsertId and RowsAffected.
var String stringType
String is a ValueConverter that converts its input to a string. If the value is already a string or []byte, it's unchanged. If the value is of another type, conversion to string is done with fmt.Sprintf("%v", v).
Functions ¶
func IsScanValue ¶
func IsScanValue(v interface{}) bool
IsScanValue reports whether v is a valid Value scan type. Unlike IsValue, IsScanValue does not permit the string type.
Types ¶
type ColumnConverter ¶
type ColumnConverter interface {
// ColumnConverter returns a ValueConverter for the provided
// column index. If the type of a specific column isn't known
// or shouldn't be handled specially, DefaultValueConverter
// can be returned.
ColumnConverter(idx int) ValueConverter
}
ColumnConverter may be optionally implemented by Stmt if the the statement is aware of its own columns' types and can convert from any type to a driver Value.
type Conn ¶
type Conn interface {
// Prepare returns a prepared statement, bound to this connection.
Prepare(query string) (Stmt, error)
// Close invalidates and potentially stops any current
// prepared statements and transactions, marking this
// connection as no longer in use.
//
// Because the sql package maintains a free pool of
// connections and only calls Close when there's a surplus of
// idle connections, it shouldn't be necessary for drivers to
// do their own connection caching.
Close() error
// Begin starts and returns a new transaction.
Begin() (Tx, error)
}
Conn is a connection to a database. It is not used concurrently by multiple goroutines.
Conn is assumed to be stateful.
type Driver ¶
type Driver interface {
// Open returns a new connection to the database.
// The name is a string in a driver-specific format.
//
// Open may return a cached connection (one previously
// closed), but doing so is unnecessary; the sql package
// maintains a pool of idle connections for efficient re-use.
//
// The returned connection is only used by one goroutine at a
// time.
Open(name string) (Conn, error)
}
Driver is the interface that must be implemented by a database driver.
type Execer ¶
Execer is an optional interface that may be implemented by a Conn.
If a Conn does not implement Execer, the db package's DB.Exec will first prepare a query, execute the statement, and then close the statement.
Exec may return ErrSkip.
type NotNull ¶
type NotNull struct {
Converter ValueConverter
}
NotNull is a type that implements ValueConverter by disallowing nil values but otherwise delegating to another ValueConverter.