{"Entry":{"collection":"protocol","key":"parameterdescription-b","name":"ParameterDescription","aliases":["ParameterDescription","Byte1('t')"],"metadata":{"aliases":["ParameterDescription","Byte1('t')"],"category":"Backend messages","content_hash":"0ff6d2d6dc8aec209913b0ecca85b83e8411faf18bf1d3f631ac071dfff8d151","imported_at":"2026-09-30T00:40:44.491878+08:00","name":"ParameterDescription","name_zh":"","slug":"parameterdescription-b","summary":"ParameterDescription is a backend protocol message. Identifies the message as a parameter description."}},"Definition":{"Collection":"protocol","Key":"parameterdescription-b","SourceDatabase":"center","Version":"18","SourceTable":"protocol_message","SourceKey":"parameterdescription-b","SourceRevision":"555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f","Facts":{"comparison_data":{"direction":"B","fields":[{"description":"Identifies the message as a parameter description.","format":"Byte1('t')"},{"description":"Length of message contents in bytes, including self.","format":"Int32"},{"description":"The number of parameters used by the statement (can be zero).","format":"Int16"},{"description":"Specifies the object ID of the parameter data type.","format":"Int32"}]},"comparison_hash":"4c97d55c0220c0daca280eccc6c33c5fc76571485d549a71e34f97327c2570ef","description":["ParameterDescription is a backend protocol message. Identifies the message as a parameter description."],"direction":"B","facts":[{"label":"Direction","value":"Backend → frontend"},{"label":"First wire field","value":"Byte1('t')"},{"label":"Field entries","value":"4"},{"label":"Documented flow contexts","value":"Extended Query"}],"fields":[{"description":"Identifies the message as a parameter description.","format":"Byte1('t')"},{"description":"Length of message contents in bytes, including self.","format":"Int32"},{"description":"The number of parameters used by the statement (can be zero).","format":"Int16"},{"description":"Specifies the object ID of the parameter data type.","format":"Int32"}],"manual_html":"\u003cdl\u003e\u003cdd\u003e\n\u003cdiv class=\"variablelist\"\u003e\n\u003cdl class=\"variablelist\"\u003e\n\u003cdt\u003e\u003cspan class=\"term\"\u003eByte1('t')\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eIdentifies the message as a parameter description.\u003c/p\u003e\n\u003c/dd\u003e\n\u003cdt\u003e\u003cspan class=\"term\"\u003eInt32\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eLength of message contents in bytes, including self.\u003c/p\u003e\n\u003c/dd\u003e\n\u003cdt\u003e\u003cspan class=\"term\"\u003eInt16\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eThe number of parameters used by the statement (can be zero).\u003c/p\u003e\n\u003c/dd\u003e\n\u003c/dl\u003e\n\u003c/div\u003e\n\u003cp\u003eThen, for each parameter, there is the following:\u003c/p\u003e\n\u003cdiv class=\"variablelist\"\u003e\n\u003cdl class=\"variablelist\"\u003e\n\u003cdt\u003e\u003cspan class=\"term\"\u003eInt32\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eSpecifies the object ID of the parameter data type.\u003c/p\u003e\n\u003c/dd\u003e\n\u003c/dl\u003e\n\u003c/div\u003e\n\u003c/dd\u003e\u003c/dl\u003e","manual_path":"/docs/18/protocol-message-formats.html","related":[{"label":"Protocol flow and exchange examples","url":"/docs/18/protocol-flow.html"},{"label":"Protocol overview","url":"/docs/18/protocol-overview.html"},{"label":"Extended Query","url":"/docs/18/protocol-flow.html#PROTOCOL-FLOW-EXT-QUERY"}],"release":{"channel":"stable","label":"18.6","major":"18","ref":"https://ftp.postgresql.org/pub/source/v18.6/postgresql-18.6.tar.bz2","revision":"555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f"},"sections":[{"paragraphs":["The complete definition below retains repetition, counts and conditional fields. A numbered table row is a documented field definition, not a fixed byte offset. Integer encodings and flow rules follow the same-version protocol chapter."],"title":"Framing and repetition"}],"signature":"ParameterDescription (B)","sources":[{"label":"PostgreSQL 18 English manual","path":"protocol-message-formats.html","sha256":"53f37652ac2c089e30ada87d8aee7bdd0f26695b03f275302e526a807d2a1f23","url":"/docs/18/protocol-message-formats.html#PROTOCOL-MESSAGE-FORMATS-PARAMETERDESCRIPTION"}],"tables":[{"columns":[{"key":"c0","label":"Position"},{"key":"c1","label":"Format"},{"key":"c2","label":"Meaning"}],"key":"fields","rows":[{"c0":"1","c1":"Byte1('t')","c2":"Identifies the message as a parameter description."},{"c0":"2","c1":"Int32","c2":"Length of message contents in bytes, including self."},{"c0":"3","c1":"Int16","c2":"The number of parameters used by the statement (can be zero)."},{"c0":"4","c1":"Int32","c2":"Specifies the object ID of the parameter data type."}],"title":"Wire fields in documented order"}]},"ManualEvidence":{"manual_path":"/docs/18/protocol-message-formats.html","release":{"channel":"stable","label":"18.6","major":"18","ref":"https://ftp.postgresql.org/pub/source/v18.6/postgresql-18.6.tar.bz2","revision":"555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f"},"sources":[{"label":"PostgreSQL 18 English manual","path":"protocol-message-formats.html","sha256":"53f37652ac2c089e30ada87d8aee7bdd0f26695b03f275302e526a807d2a1f23","url":"/docs/18/protocol-message-formats.html#PROTOCOL-MESSAGE-FORMATS-PARAMETERDESCRIPTION"}]},"MeasuredEvidence":{}},"Text":{"Collection":"protocol","Key":"parameterdescription-b","SourceDatabase":"center","Version":"18","Locale":"en","Title":"ParameterDescription","Summary":"ParameterDescription is a backend protocol message. Identifies the message as a parameter description.","BodyHTML":"\u003cdl\u003e\u003cdd\u003e\n\u003cdiv\u003e\n\u003cdl\u003e\n\u003cdt\u003e\u003cspan\u003eByte1(\u0026#39;t\u0026#39;)\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eIdentifies the message as a parameter description.\u003c/p\u003e\n\u003c/dd\u003e\n\u003cdt\u003e\u003cspan\u003eInt32\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eLength of message contents in bytes, including self.\u003c/p\u003e\n\u003c/dd\u003e\n\u003cdt\u003e\u003cspan\u003eInt16\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eThe number of parameters used by the statement (can be zero).\u003c/p\u003e\n\u003c/dd\u003e\n\u003c/dl\u003e\n\u003c/div\u003e\n\u003cp\u003eThen, for each parameter, there is the following:\u003c/p\u003e\n\u003cdiv\u003e\n\u003cdl\u003e\n\u003cdt\u003e\u003cspan\u003eInt32\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eSpecifies the object ID of the parameter data type.\u003c/p\u003e\n\u003c/dd\u003e\n\u003c/dl\u003e\n\u003c/div\u003e\n\u003c/dd\u003e\u003c/dl\u003e","SourceRevision":"555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f","ContentHash":"9b8c902d913d120f0854b347ec8079d599a5f0a312a1e45c1cab554c9d9b7ad2","Payload":{"description":["ParameterDescription is a backend protocol message. Identifies the message as a parameter description."],"manual_html":"\u003cdl\u003e\u003cdd\u003e\n\u003cdiv class=\"variablelist\"\u003e\n\u003cdl class=\"variablelist\"\u003e\n\u003cdt\u003e\u003cspan class=\"term\"\u003eByte1('t')\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eIdentifies the message as a parameter description.\u003c/p\u003e\n\u003c/dd\u003e\n\u003cdt\u003e\u003cspan class=\"term\"\u003eInt32\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eLength of message contents in bytes, including self.\u003c/p\u003e\n\u003c/dd\u003e\n\u003cdt\u003e\u003cspan class=\"term\"\u003eInt16\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eThe number of parameters used by the statement (can be zero).\u003c/p\u003e\n\u003c/dd\u003e\n\u003c/dl\u003e\n\u003c/div\u003e\n\u003cp\u003eThen, for each parameter, there is the following:\u003c/p\u003e\n\u003cdiv class=\"variablelist\"\u003e\n\u003cdl class=\"variablelist\"\u003e\n\u003cdt\u003e\u003cspan class=\"term\"\u003eInt32\u003c/span\u003e\u003c/dt\u003e\n\u003cdd\u003e\n\u003cp\u003eSpecifies the object ID of the parameter data type.\u003c/p\u003e\n\u003c/dd\u003e\n\u003c/dl\u003e\n\u003c/div\u003e\n\u003c/dd\u003e\u003c/dl\u003e","related":[{"label":"Protocol flow and exchange examples","url":"/docs/18/protocol-flow.html"},{"label":"Protocol overview","url":"/docs/18/protocol-overview.html"},{"label":"Extended Query","url":"/docs/18/protocol-flow.html#PROTOCOL-FLOW-EXT-QUERY"}],"sections":[{"paragraphs":["The complete definition below retains repetition, counts and conditional fields. A numbered table row is a documented field definition, not a fixed byte offset. Integer encodings and flow rules follow the same-version protocol chapter."],"title":"Framing and repetition"}],"tables":[{"columns":[{"key":"c0","label":"Position"},{"key":"c1","label":"Format"},{"key":"c2","label":"Meaning"}],"key":"fields","rows":[{"c0":"1","c1":"Byte1('t')","c2":"Identifies the message as a parameter description."},{"c0":"2","c1":"Int32","c2":"Length of message contents in bytes, including self."},{"c0":"3","c1":"Int16","c2":"The number of parameters used by the statement (can be zero)."},{"c0":"4","c1":"Int32","c2":"Specifies the object ID of the parameter data type."}],"title":"Wire fields in documented order"}]}},"RequestedLocale":"zh-Hans","Fallback":true,"Versions":["10","11","12","13","14","15","16","17","18","19","20"],"Locales":["en"],"Signatures":null,"Spellings":null,"SQLState":null,"Evidence":null}