Module protocol 

TDS — the Tabular Data Stream protocol SQL Server speaks.

Everything travels in packets: an eight-byte header and a payload, with a message being the run of packets ending in one whose status carries the end-of-message bit. Requests are built as one payload and split by split_message; responses are reassembled and then read as a stream of tokens by TokenStream.

Unlike PostgreSQL, TDS is little-endian everywhere except the packet header, whose length and SPID are network order. That single inconsistency is the source of most first-attempt bugs, so the header has its own type rather than being read inline.

Modules

encryption

The values the ENCRYPTION option can carry, in both directions.

packet

Packet types, from the Type byte of the header.

prelogin_option

PRELOGIN option tokens.

status

Status bits from the Status byte of the header.

token

Token identifiers from the response stream.

Structs

Done

Login7

Everything LOGIN7 carries that is not a constant.

LoginAck

The LOGINACK that says the credentials were accepted.

PacketHeader

The eight bytes in front of every packet.

PreloginResponse

What the server answered in its PRELOGIN.

Reader

A cursor over a reassembled message.

RpcParameter

One parameter of an RPC call: a name and its already-encoded type and value.

ServerError

An error or an informational message from the server.

TokenStream

Reads a reassembled response message one token at a time.

Enums

DoneKind

Which of the three DONE tokens arrived.

EnvChange

A change of session state the server announces rather than being asked.

Token

Constants

DEFAULT_PACKET_SIZE

The packet size assumed before the server says otherwise.

HEADER_LEN

The fixed size of a packet header.

SP_EXECUTESQL

The well-known procedure id of sp_executesql.

TDS_VERSION_7_4

TDS 7.4, which is what SQL Server 2012 and later speak.

Functions

all_headers

The ALL_HEADERS block every batch and RPC carries in TDS 7.2 and later.

decode_ucs2

Decode UTF-16LE, which TDS calls UCS-2 and uses for every string it sends.

execute_sql

Build the sp_executesql call for a parameterised statement.

login7

parse_prelogin

prelogin

Build a PRELOGIN payload asking for a particular encryption level.

rpc

split_message

Frame a payload as one or more packets of at most packet_size bytes.

sql_batch

A statement with no parameters, sent as text.