ies payroll

, very happy. Unfortunately, the leadership found that the amount of wages issued to Singo is not correct, is 2000 yuan, and then quickly rolled back to business, modify the amount, the transaction will be submitted, and finally singo the actual salary of only 2000 yuan, Singo empty joy a game. The above situation, that is what we call dirty read , two concurrent transactions, "transaction A: lead to Singo payroll", "Transaction B:singo query

, very happy. Unfortunately, the leadership found that the amount of wages issued to Singo is not correct, is 2000 yuan, and then quickly rolled back to business, modify the amount, the transaction will be submitted, and finally singo the actual salary of only 2000 yuan, Singo empty joy a game.The above situation, that is what we call dirty Read, two concurrent transactions, "transaction A: lead to Singo payroll", "Transaction B:singo query

DEPTNO Department Number, COUNT (*) as department number, sum (SAL) departmental payroll sum from EMP GROUP by DEPTNO ORDER by SUM (SAL) DESC;The results are not posted, and you can see that the entire EMP table is divided into three pieces of data, each piece of data for a department, for the group function, it does not care about each group in the end is composed of who, or relative to the individual, the group function is to stand on a macro point

the following definitions to control the method and the overriding of the attributes Overridable--Let the attributes and methods in the inheritance of Class can override Overrides--Defining the nature or method of which foundation to override NotOverridable (Preset)--class override to prevent belonging or methods from being inherited MustOverride--requires that the class of inheritance must be override or method Code examples such as the lower Imports System Namespace MyName

, is 2000 yuan, and then quickly rolled back to business, modify the amount, the transaction will be submitted, and finally singo the actual salary of only 2000 yuan, Singo empty joy a game. The above situation, that is what we call dirty Read, two concurrent transactions, "transaction A: lead to Singo payroll", "Transaction B:singo query Payroll account", transaction B read the transaction A has not yet

committed X √ √ REPEATABLE READ X X √ Serializable X X X Note: We discuss the isolation level scenario, mainly in the case of multiple transactions concurrency, so the next explanation is around the transaction concurrency. READ UNCOMMITTED not submitted The company paid, the leader of the 5000 yuan to the Singo account, but the transaction did not submit, and Singo just to check the account, found that the salary has been t

Singo is not correct, is 2000 yuan, and then quickly rolled back to business, modify the amount, the transaction will be submitted, and finally singo the actual salary of only 2000 yuan, Singo empty joy a game.The above situation, that is what we call dirty Read, two concurrent transactions, "transaction A: lead to Singo payroll", "Transaction B:singo query Payroll account", transaction B read the transact

. Unfortunately, the leadership found that the amount of wages issued to Singo is not correct, is 2000 yuan, and then quickly rolled back to business, modify the amount, the transaction will be submitted, and finally singo the actual salary of only 2000 yuan, Singo empty joy a game. The above situation, that is what we call dirty Read, two concurrent transactions, "transaction A: lead to Singo payroll", "Transaction B:singo query

yuan to the Singo account, but the transaction did not submit, and Singo just to check the account, found that the salary has been to the account, is 5000 yuan whole, very happy. Unfortunately, the leadership found that the amount of wages issued to Singo is not correct, is 2000 yuan, and then quickly rolled back to business, modify the amount, the transaction will be submitted, and finally singo the actual salary of only 2000 yuan, Singo empty joy a game. The above situation, that is what we

yuan to the Singo account, but the transaction did not submit, and Singo just to check the account, found that the salary has been to the account, is 5000 yuan whole, very happy. Unfortunately, the leadership found that the amount of wages issued to Singo is not correct, is 2000 yuan, and then quickly rolled back to business, modify the amount, the transaction will be submitted, and finally singo the actual salary of only 2000 yuan, Singo empty joy a game. The above situation, that is what we

multiple transactions concurrency, so the next explanation is around the transaction concurrency. READ UNCOMMITTED not submittedThe company paid, the leader of the 5000 yuan to the Singo account, but the transaction did not submit, and Singo just to check the account, found that the salary has been to the account, is 5000 yuan whole, very happy. Unfortunately, the leadership found that the amount of wages issued to Singo is not correct, is 2000 yuan, and then quickly rolled back to business, mo

the account, found that the salary has been to the account, is 5000 yuan whole, very happy. Unfortunately, the leadership found that the amount of wages issued to Singo is not correct, is 2000 yuan, and then quickly rolled back to business, modify the amount, the transaction will be submitted, and finally singo the actual salary of only 2000 yuan, Singo empty joy a game. The above situation, that is what we call dirty Read, two concurrent transactions, "transaction A: lead to Singo

good:Add a p3p header to the response.Response (). addheader ("p3p", "cp = \" idc dsp cor Cura ADMA our ind PHY onl com sta \""); CP = "xxx xxxx" has specific meanings:CP is the meaning of Compact into ies,In addition, the header value can also be policyref = "http: // myhost/p3p/policyreferences. xml", which is to specify a policy file. For details, see here. The following is the specific range and meaning of the value of the extracted compact polic

　　Perhaps you have completed hundreds of financial statements in Excel, perhaps you have used Excel functions to achieve thousands of complex operations, you may think that Excel is too much, or even new. but the countless times we routinely use the handy method is just 1% of all Excel skills. This topic from excel in some of the little-known skills to get a glimpse of the different aspects of Excel style. 　　Let different types of data be displayed in different colors In the

are generally used to add similar inspection steps in multiple places. Once the consistency check process has been adjusted, it will inevitably result in multiple local modifications, not only increasing the workload, but also not guaranteeing the correctness of each inspection step. The application of triggers should be placed on the key, multi-initiator, high-frequency access data tables, excessive use of triggers, will increase the database burden, reduce database performance. Discarding the

diagram, which are all the data of table B and a common part of table A and B, denoted by sql:Select * from dept_manager s right jointitles t on t. Emp_no = s. Emp_no This statement queries all the data in table B, if there is data in table A and matches in B table (via Emp_no), then a table shows the matching data, otherwise null is shown, the following is the data display:The above is the most common Join association Query method, the following for the above join to add conditi

Maybe you have already completed hundreds of financial statements in Excel. Maybe you have used the EXCEL function to perform thousands of complex operations. Maybe you think that excel is just the same, or even nothing new. However, we repeatedly tried to use Excel 1% of all the skills on a daily basis. This topic starts with some little-known skills in Excel to learn about the different styles of Excel.1. display different types of data in different colorsIn the

user and mode, user and schema. I finally figured out what schema is, so let's talk about why schema is needed. Continue.2. Why do I need the mode? In many cases, I need to know what the concept is and why it is needed. In this way, we will remember more firmly, become more interested, and make changes and innovations. Why do we need a mode? We know that users need a password to log on, and the mode corresponds to users one by one. By the way, this is a security consideration. Think about it. J

transaction did not submit, and Singo just to check the account, found that the salary has been to the account, is 5000 yuan whole, very happy. Unfortunately, the leadership found that the amount of wages issued to Singo is not correct, is 2000 yuan, and then quickly rolled back to business, modify the amount, the transaction will be submitted, and finally singo the actual salary of only 2000 yuan, Singo empty joy a game. The above situation, that is what we call dirty Read, two concurrent tra

In order to explain the problem in the simplest way, I have specially designed a table like this one.　　first, GROUP by single-value rulesRule 1: Single-value rules, followed by the list after select, must be returned and only one value returned for each grouping. The typical performance is the column following the select, which must appear after the GROUP BY clause if no aggregate function is used.As the following query error:　　Because after grouping by department, there are 3 numbers in the tec