(12.2)Type "help"forhelp.test=# \dtListofrelationsSchema|Name|Type|Owner---+---+---+---public|cpc_sketch_test|table|csqjxiaopublic|test_table|table|csqjxiao(2rows)test=# \d test_tableTable"public.test_table"Column|Type|Collation|Nullable|Default---+---+---+---+---id|integer|...
SUBTYPEfinishtimeIStimerec;-- based on RECORD type SUBTYPEid_numISemp.empno%TYPE;-- based on column type 我们可以使用%TYPE或%ROWTYPE来指定基类型。当%TYPE提供数据库字段中的数据类型时,子类型继承字段的大小约束(如果有的话)。但是,子类型并不能继承其他约束,如NOT NULL。 2、使用子类型 一旦我们定义...
myrow tablename%ROWTYPE; myfield tablename.columnname%TYPE; arow RECORD; 2.1 Declaring Function Parameters Parameters passed to functions are named with the identifiers $1, $2 give a name to the parameter in the CREATE FUNCTION command, for example: CREATEFUNCTIONsales_tax(subtotalreal)RETURNSr...
PostgreSQL creates check constraints with the default name in the _<columnname>_check format, as shown below.You can also specify a custom name of your check constraints using CONSTRAINT <constraint-name> check(condition) with the column, as shown below. Example: Check...
/* Need a tuple descriptor representing a single TEXT or XML column */ tupdesc = CreateTemplateTupleDesc(1); TupleDescInitEntry(tupdesc, (AttrNumber) 1, "QUERY PLAN", result_type, -1, 0); return tupdesc;}/* * ExplainOneQuery - * print out the execution plan for one Query * * ...
|RETURNSTABLE ( column_name column_type [, ...] ) ] { LANGUAGE lang_name |TRANSFORM{ FOR TYPE type_name } [, ... ] |WINDOW|IMMUTABLE|STABLE|VOLATILE|[ NOT] LEAKPROOF |CALLEDON NULL INPUT |RETURNSNULL ON NULL INPUT |STRICT|[ EXTERNAL] SECURITY INVOKER |[ EXTERNAL] SECURITY DEFINER ...
为单个列创建B-tree索引：CREATEINDEXindex_nameONtable_name(column_name);为单个列创建Hash索引：CREATE...
* * The subsidiary ScanKey array appears in logical column order of the row * comparison, which may be different from index column order. The array * elements are like a normal ScanKey array except that: * sk_flags must include SK_ROW_MEMBER, plus SK_ROW_END in the last * element (...
This can cause unexpected issues; consider that when you store now() into such a column, you might be storing a value half a second in the future. When should you? Never. Don’t use +/-HH:mm as a text Time Zone name Why not? PostgreSQL doesn’t accept fixed time zone offsets...
EXECUTE 'UPDATE tbl SET ' || quote_ident(colname) || ' = ' || quote_literal(newvalue) || ' WHERE key = ' || quote_literal(keyvalue); This example demonstrates the use of the quote_ident and quote_literal functions (see Section 9.4). For safety, expressions containing column or ta...