MySQL--连接属性

The capability flags are used by the client and server to indicate which features they support and want to use.

Protocol::CapabilityFlags:

CLIENT_LONG_PASSWORD

Use the improved version of

Old Password Authentication

.

Note
Assumed to be set since 4.1.1.

Value
0x00000001

CLIENT_FOUND_ROWS

Send

found rows

instead of

affected rows

in

EOF_Packet

.

Value
0x00000002

CLIENT_LONG_FLAG

Longer flags in

Protocol::ColumnDefinition320

.

Value
0x00000004

Server
Supports longer flags.

Client
Expects longer flags.

CLIENT_CONNECT_WITH_DB

Database (schema) name can be specified on connect in

Handshake Response Packet

.

Value
0x00000008

Server
Supports schema-name in

Handshake Response Packet

.

Client

Handshake Response Packet

contains a schema-name.

CLIENT_NO_SCHEMA

Value
0x00000010

Server
Do not permit

database.table.column

.

CLIENT_COMPRESS

Compression protocol supported.

Value
0x00000020

Server
Supports compression.

Client
Switches to Compression compressed protocol after successful authentication.

CLIENT_ODBC

Value
0x00000040

Special handling of ODBC behavior.

Note
No special behavior since 3.22.

CLIENT_LOCAL_FILES

Can use

LOAD DATA LOCAL

.

Value
0x00000080

Server
Enables the LOCAL INFILE request of LOAD DATA|XML.

Client
Will handle LOCAL INFILE request.

CLIENT_IGNORE_SPACE

Value
0x00000100

Server
Parser can ignore spaces before

'('

.

Client
Let the parser ignore spaces before

'('

.

CLIENT_PROTOCOL_41

Value
0x00000200

Server
Supports the 4.1 protocol.

Client
Uses the 4.1 protocol.

Note
this value was

CLIENT_CHANGE_USER

in 3.22, unused in 4.0

CLIENT_INTERACTIVE

wait_timeout

versus

wait_interactive_timeout

.

Value
0x00000400

Server
Supports interactive and noninteractive clients.

Client
Client is interactive.

See
mysql_real_connect()

CLIENT_SSL

Value
0x00000800

Server
Supports SSL.

Client
Switch to SSL after sending the capability-flags.

CLIENT_IGNORE_SIGPIPE

Value
0x00001000

Client
Do not issue

SIGPIPE

if network failures occur (libmysqlclient only).

See
mysql_real_connect()

CLIENT_TRANSACTIONS

Value
0x00002000

Server
Can send status flags in

EOF_Packet

.

Client
Expects status flags in

EOF_Packet

.

Note
This flag is optional in 3.23, but always set by the server since 4.0.

CLIENT_RESERVED

Unused.

Value
0x00004000

Note
Was named

CLIENT_PROTOCOL_41

in 4.1.0.

CLIENT_SECURE_CONNECTION

Value
0x00008000

Server
Supports

Authentication::Native41

.

Client
Supports

Authentication::Native41

.

CLIENT_MULTI_STATEMENTS

Value
0x00010000

Server
Can handle multiple statements per

COM_QUERY

and

COM_STMT_PREPARE

.

Client
May send multiple statements per

COM_QUERY

and

COM_STMT_PREPARE

.

Note
Was named

CLIENT_MULTI_QUERIES

in 4.1.0, renamed later.

Requires

CLIENT_PROTOCOL_41

CLIENT_MULTI_RESULTS

Value
0x00020000

Server
Can send multiple resultsets for

COM_QUERY

.

Client
Can handle multiple resultsets for

COM_QUERY

.

Requires

CLIENT_PROTOCOL_41

CLIENT_PS_MULTI_RESULTS

Server
Can send multiple resultsets for

COM_STMT_EXECUTE

.

Client
Can handle multiple resultsets for

COM_STMT_EXECUTE

.

Value
0x00040000

Requires

CLIENT_PROTOCOL_41

CLIENT_PLUGIN_AUTH

Value
0x00080000

Server
Sends extra data in Initial Handshake Packet and supports the pluggable authentication protocol.

Client
Supports authentication plugins.

Requires

CLIENT_PROTOCOL_41

CLIENT_CONNECT_ATTRS

Value
0x00100000

Server
Permits connection attributes in

Protocol::HandshakeResponse41

.

Client
Sends connection attributes in

Protocol::HandshakeResponse41

.

CLIENT_PLUGIN_AUTH_LENENC_CLIENT_DATA

Value
0x00200000

Server
Understands length-encoded integer for auth response data in

Protocol::HandshakeResponse41

.

Client
Length of auth response data in

Protocol::HandshakeResponse41

is a length-encoded integer.

Note
The flag was introduced in 5.6.6, but had the wrong value.

CLIENT_CAN_HANDLE_EXPIRED_PASSWORDS

Value
0x00400000

Server
Announces support for expired password extension.

Client
Can handle expired passwords.

CLIENT_SESSION_TRACK

Value
0x00800000

Server
Can set SERVER_SESSION_STATE_CHANGED in the Status Flags and send session-state change data after a OK packet.

Client
Expects the server to send sesson-state changes after a OK packet.

CLIENT_DEPRECATE_EOF

Value
0x01000000

Server
Can send OK after a Text Resultset.

Client
Expects an OK (instead of EOF) after the resultset rows of a Text Resultset.

Background
To support

CLIENT_SESSION_TRACK

, additional information must be sent after all successful commands. Although the OK packet is extensible, the EOF packet is not due to the overlap of its bytes with the content of the Text Resultset Row.

Therefore, the EOF packet in the Text Resultset is replaced with an OK packet. EOF packets are deprecated as of MySQL 5.7.5.