如何确保非负柱？

Question

我需要创建一个Branch包含列branch_name和branch_city字符类型的表,assets作为整数类型.branch_name是主键,我必须确保assets是非负面的.

我尝试过

CREATE TABLE Branch
(
    branch_name navarchar(100) primary key,
    branch_city nvarchar(100),
    assests int NOT NULL
)

Answer 1

您需要为主键定义数据类型,并且需要添加CHECK约束以确保assets非负数:

CREATE TABLE dbo.Branch
(
    branch_name NVARCHAR(100) primary key,
    branch_city nvarchar(100),
    assets int NOT NULL CHECK (assets >= 0)
)

Answer 2

更改表格,创建约束以检查列

ALTER TABLE Branch ADD CONSTRAINT chkassets CHECK (assets > 0);