diff options
Diffstat (limited to 'src/database/sql/sql.go')
| -rw-r--r-- | src/database/sql/sql.go | 44 |
1 files changed, 40 insertions, 4 deletions
diff --git a/src/database/sql/sql.go b/src/database/sql/sql.go index d363008993..3cef4b6404 100644 --- a/src/database/sql/sql.go +++ b/src/database/sql/sql.go @@ -15,6 +15,7 @@ package sql import ( "context" "database/sql/driver" + "database/sql/internal" "errors" "fmt" "io" @@ -89,6 +90,38 @@ func Param(name string, value interface{}) NamedParam { return NamedParam{Name: name, Value: value} } +// IsolationLevel is the transaction isolation level stored in Context. +// The IsolationLevel is set with IsolationContext and the context +// should be passed to BeginContext. +type IsolationLevel int + +// Various isolation levels that drivers may support in BeginContext. +// If a driver does not support a given isolation level an error may be returned. +const ( + LevelDefault IsolationLevel = iota + LevelReadUncommited + LevelReadCommited + LevelWriteCommited + LevelRepeatableRead + LevelSnapshot + LevelSerializable + LevelLinearizable +) + +// IsolationContext returns a new Context that carries the provided isolation level. +// The context must contain the isolation level before beginning the transaction +// with BeginContext. +func IsolationContext(ctx context.Context, level IsolationLevel) context.Context { + return context.WithValue(ctx, internal.IsolationLevelKey{}, driver.IsolationLevel(level)) +} + +// ReadOnlyWithContext returns a new Context that carries the provided +// read-only transaction property. The context must contain the read-only property +// before beginning the transaction with BeginContext. +func ReadOnlyContext(ctx context.Context) context.Context { + return context.WithValue(ctx, internal.ReadOnlyKey{}, true) +} + // RawBytes is a byte slice that holds a reference to memory owned by // the database itself. After a Scan into a RawBytes, the slice is only // valid until the next call to Next, Scan, or Close. @@ -1224,7 +1257,10 @@ func (db *DB) QueryRow(query string, args ...interface{}) *Row { return db.QueryRowContext(context.Background(), query, args...) } -// BeginContext starts a transaction. If a non-default isolation level is used +// BeginContext starts a transaction. +// +// An isolation level may be set by setting the value in the context +// before calling this. If a non-default isolation level is used // that the driver doesn't support an error will be returned. Different drivers // may have slightly different meanings for the same isolation level. func (db *DB) BeginContext(ctx context.Context) (*Tx, error) { @@ -2212,9 +2248,9 @@ func (rs *Rows) isClosed() bool { return atomic.LoadInt32(&rs.closed) != 0 } -// Close closes the Rows, preventing further enumeration. If Next and -// NextResultSet both return -// false, the Rows are closed automatically and it will suffice to check the +// Close closes the Rows, preventing further enumeration. If Next is called +// and returns false and there are no further result sets, +// the Rows 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 (rs *Rows) Close() error { if !atomic.CompareAndSwapInt32(&rs.closed, 0, 1) { |