SQL语句PART7
Merge statement
function benefits: 1) provides the ability to conditionally update, insert or delete data into a database table. 2) performs an update if the row exists, and an insert if it is a new row. --> 1) avoids seperate updates, 2) increase performance and ease of use. 3) is useful in data warehousing applications.
syntax:
MERGE INTO table_name table_alias
USING (table|view|sub_query) alias
ON (join condition)
WHEN MATCHED THEN
UPDATE SET
col1 = col1_val,
col2 = col2_val
WHEN NOT MATCHED THEN
INSERT (column_list)
VALUES (column_values);
e.g.: table: temp_t1:
results:
1 1 收文 SHOUWEN
2 1 发文 FAWEN
3 1 交办 JIAOBAN
4 2 值班报告 REPORT
5 3 督察督办 SUPERVISAL
6 2 值班快报 DAILYREPORT
7 2 我的事情 NOTIFY
8 4 提案 RESOLUTION
9 4 建议 SUGGESTION
e.g.: table: temp_t2：
results:
1 1 收文 SHOUWEN
2 1 发文 FAWEN
3 1 交办 JIAOBAN
4 2 值班报告 REPORT
5 3 督察督办
相关文档：
using System;
using System.Text.RegularExpressions;
using Microsoft.SqlServer.Server;
public partial class UserDefinedFunctions
{
[Microsoft.SqlServer.Server.SqlFunction(IsDeterministic = true,IsPrecise = true)]
public static bool RegExIsMatch(string pattern,string matchString)
{
......
4、对象依赖性
CREATE OR REPLACE TYPE Obj1 AS OBJECT (
f1 NUMBER,
f2 VARCHAR2(10),
f3 DATE
);
/
CREATE OR REPLACE TYPE Obj2 AS OBJECT (
f1 DATE,
f2 CHAR(1)
);
/
CREATE OR REPLACE TYPE Obj3 AS OBJECT (
a Obj1,
b Obj2
);
/
OBJ3依赖于OBJ ......
--1加内存表
EXEC sp_tableoption '表名','pintable', 'true'
--2卸载内存表
EXEC sp_tableoption '表名','pintable', 'false'
--2查询是否有内存表驻留
SELECT * from INFORMATION_SCHEMA.Tables
WHERE TABLE_TYPE = 'BASE TABLE'
AND OBJECTPROP ......
Confirming granted privileges
Data Dictionary View Description
ROLE_SYS_PRIVS System privileges granted to roles
ROLE_TAB_PRIVS & ......
Differring Constraints:
Constraints can have the following attributes: DEFFERRABLE / NOT DEFFERRABLE, INITIALLY DEFFERRED / INITIALLY IMMEDIATE.
e.g.:
alter table dept2 add constraint dept2_id_pk primary key (department_id) deferrable initially deferred; // deferring constraint on creation. ......
