是一种用于验证数据格式的规则,它可以在数据库中定义,以确保插入或更新的数据符合特定的模式。正则表达式是一种强大的文本匹配工具,可以用于检查字符串是否符合特定的模式。 在MsSQL中,可以使用正则表达...
constraint CK_p_shequname check(count between 1 and 1000) } 创建check约束 CK_p_count, p_count输入的数字在1到1000之间,否则出错.
在SQL Server 中有5 种约束:主关键字约束(Primary Key Constraint)、外关键字约束(Foreign Key Constraint)、惟一性约束(Unique Constraint)、检查约束(Check Constraint)和缺省约束(Default Constraint)。 7.2.1 主关键字约束 主关键字约束指定表的一列或几列的组合的值在表中具有惟一性,即能惟一地指定一行记录。...
SQL CHECK Constraint on ALTER TABLE 如果在表已存在的情况下为 "Id_P" 列创建 CHECK 约束,请使用下面的 SQL: MySQL / SQL Server / Oracle / MS Access: ALTER TABLE PersonsADD CHECK (Id_P>0) 1. 如果需要命名 CHECK 约束,以及为多个列定义 CHECK 约束,请使用下面的 SQL 语法: MySQL / SQL Server...
主键约束(PK) Primary key constraint 唯一约束(UQ) Unique constraint 默认约束(DF) Default constraint 检查约束(CK) Check constraint 外键约束(FK) Foreign key constraint 我们首先来创建一张表teacher createtableteacher ( tIdintnotnull, tname nvarchar(50), ...
Subclause 11.9, "<check constraint definition>": <check constraint definition> ::= CHECK <left paren> <search condition> <right paren> ... Conformance Rules Without Feature F672, "Retrospective check constraints", conforming SQL language shall not contain a <check constraint definition> that ...
INSERT INTO CheckTbl VALUES (10, 10) GO DELETE CheckTbl WHERE col1 = 10; The DELETE statement succeeds, even though the CHECK constraint specifies that table CheckTbl must have at least 1 row. See Also Reference CREATE TABLE (Transact-SQL) ALTER TABLE (Transact-SQL) DROP TABLE (Trans...
Subclause 8.5, "<XML valid predicate>": Without Feature X145, "IS VALID predicate outside check constraints", conforming SQL language shall not contain an <XML valid predicate> that is not directly contained in the <search condition> of a <check constraint definition>. ...
const sql = require('mssql') const sqlConfig = { user: process.env.DB_USER, password: process.env.DB_PWD, database: process.env.DB_NAME, server: 'localhost', pool: { max: 10, min: 0, idleTimeoutMillis: 30000 }, options: { encrypt: true, // for azure trustServerCertificate: fa...
2.1.2.95 F693, SQL-session and client module collations 2.1.2.96 F695, Translation support 2.1.2.97 F701, Referential update actions 2.1.2.98 F711, ALTER domain 2.1.2.99 F721, Deferrable constraints 2.1.2.100 F741, Referential MATCH types 2.1.2.101 F751, View CHECK enhancements 2.1.2....