(3)No action方式:如果子表中有匹配的记录,则不允许对父表对应候选键进行update/delete操作 这个是ANSI SQL-92标准,从mysql4.0.8开始支持; --无参照完整性关系,有了也不生效。 1. (4)set null方式:在父表上update/delete记录时,将子表上匹配记录的列设为null 要注意子表的外键列不能为not null On delet...
SQL function "text_to_date" statement 1 ... 正确方法 create or replace function text_to_date(text) returns date as $$ select to_date($1,'yyyy-mm-dd'); $$ language sql strict; create cast (text as date) with function text_to_date(text) as implicit; postgres=# select ...
function get(options?: RequestParameters): StreamableMethod<BoundariesGetCascadeDeleteJobDetails200Response | BoundariesGetCascadeDeleteJobDetailsDefaultResponse> 参数 options RequestParameters 返回 StreamableMethod<BoundariesGetCascadeDeleteJobDetails200Response | BoundariesGetCascadeDeleteJobDetail...
}functionOnDelete(meta){// Ignores all keys not matching "user_#" and allows other types in the source collectionif((meta.id).startsWith("user_") ==false)return;// Implements a contrived filter and keeps all user transactions where the user_id > 100varid = meta.id;varnumeric_id =par...
function get(options?: RequestParameters): StreamableMethod<InsightsGetCascadeDeleteJobDetails200Response | InsightsGetCascadeDeleteJobDetailsDefaultResponse> 參數 options RequestParameters 傳回 StreamableMethod<InsightsGetCascadeDeleteJobDetails200Response | InsightsGetCascadeDeleteJobDetailsDefaultResponse>put...
08_SQL函数_1(08_sql_function_1) 16分 33秒 高清 下载 09_SQL函数_2(09_sql_function_2) 06分 14秒 高清 下载 10_群函数(10_group_function) 08分 10秒 高清 下载 11_小组通过(11_group_by) 09分 33秒 高清 下载 12_有(12_having) 07分 21秒 高清 下载 13_子查询 11分 44秒 高清...
IN (SELECT emp_id FROM JobAssignments UNION SELECT emp_id FROM Personnel))); However, that is overkill and does not prevent an employee from being at more than one store. There are probably indexes on the SSN values in both Personnel and JobAssignments, so getting a COUNT() function shoul...
In this table, the P_ID column is a foreign key referencing the P_ID column in the Persons table −Open Compiler CREATE TABLE Films_watched ( P_ID INT, F_NO INT, F_NAME varchar(40), PRIMARY KEY(P_ID,F_NO), FOREIGN KEY(P_ID) REFERENCES PERSONS(P_ID) ON DELETE CASCADE ); ...
BuiltInFunctionTableReference BulkInsertBase BulkInsertOption BulkInsertOptionKind BulkInsertStatement BulkOpenRowset CallTarget CaseExpression CastCall CatalogCollation CatalogCollationOption CellsPerObjectSpatialIndexOption CertificateCreateLoginSource CertificateOption CertificateOptionKinds CertificateStatementBas...
08_SQL函数_1(08_sql_function_1) 16分 33秒 高清 下载 09_SQL函数_2(09_sql_function_2) 06分 14秒 高清 下载 10_群函数(10_group_function) 08分 10秒 高清 下载 11_小组通过(11_group_by) 09分 33秒 高清 下载 12_有(12_having) 07分 21秒 高清 下载 13_子查询 11分 44秒 高清...