SQLPrimaryKeys 會以標準結果集的形式傳回結果,依TABLE_CAT、TABLE_SCHEM、TABLE_NAME和KEY_SEQ排序。 如需如何使用這項資訊的資訊,請參閱 目錄資料的 使用方式。下列資料行已針對 ODBC 3 重新命名。 x . 資料行名稱變更不會影響回溯相容性,因為應用程式會依資料行編號系結。
The primary key creates aCLUSTEREDindex on the column(s) by default in many databases. The specific syntax for working with primary keys may vary slightly depending on the SQL dialect you're using (such as MySQL, PostgreSQL, SQL Server, etc.), so always check the specific documentation for ...
返回指定远程表的主键列,每个键列对应一行。Transact-SQL 语法约定语法syntaxsql 复制 sp_primarykeys [ @table_server = ] N'table_server' [ , [ @table_name = ] N'table_name' ] [ , [ @table_schema = ] N'table_schema' ] [ , [ @table_catalog = ] N'table_catalog' ] [ ;...
FOREIGN KEY (PersonID) REFERENCES Persons(PersonID) ); 在多个列上建立外键: To allow naming of a FOREIGN KEYconstraint, and for defining a FOREIGN KEY constraint on multiple columns, use the following SQLsyntax: MySQL / SQL Server / Oracle / MS Access: CREATE TABLE Orders ( OrderID int NO...
Drop the Primary Key in SQL Server To Drop the Primary Key, we use the below syntax. It does not matter if the Primary Key was on single or multiple columns. ALTER TABLE <schema_name>. DROP CONSTRAINT <constraint_name> ; To drop the ...
SQL Server / Oracle / MS Access: CREATETABLEPersons ( ID intNOTNULLPRIMARYKEY, LastName varchar(255)NOTNULL, FirstName varchar(255), Age int ); To allow naming of aPRIMARY KEYconstraint, and for defining aPRIMARY KEYconstraint on multiple columns, use the following SQL syntax: ...
(CONSTRAINT PK_EMP PRIMARY KEY (EMPNO)) / ALTER TABLE EMP ADD (CONSTRAINT FK_DEPTNO FOREIGN KEY (DEPTNO) REFERENCES DEPT (DEPTNO)) / 01.Tom Said user_constraints would be the place I would look for constraints. user_dependencies -- well, that I would use to see who relies on who. ...
Technically, a primary key constraint is the combination of a not-null constraint and a UNIQUE constraint. Typically, you define primary for a table when creating it: CREATE TABLE table_name ( column_1 data_type PRIMARY KEY, column_2 data_type, … ); In this syntax, you define the prima...
Syntax: CREATE TABLE column1 data_type[(size)] NOT NULL PRIMARY KEY, column2 data_type[(size)], ...); Parameters: Good practice for primary keys in tables Primary keys should be as small as necessary. Prefer a numeric type because numeric types are stored in a much more compact forma...
MYSQL # 1064:你有一个错误在您的SQL syntaxr主键数量的 创建表(同时查阅客房 room_type_id主键,room_type_num varchar2(10)不空,room_type_name varchar2 NOT NULL(50),bed_num号码,room_unit_price数量(5,2),clock_room varchar2(4),clock_room_price数量(5,2),room_foregift数量(5,2)...