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The time-consuming problem of batch storage of a large amount of data in Mysql:, why does the speed decline so fast when the amount of data is large?
mybatis+mysql for java projects
int batchAmount = 20000;
for (int startIndex = 0; startIndex < size; startIndex += batchAmount) {
int endIndex = startIndex + batchAmount;
endIndex = (endIndex &...
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Is there a framework similar to hibernate,mongoose for node.js to mysql?
recently, when I was writing a node project, I found that it was troublesome to write a bunch of sql statements when connecting to mysql with node.js. I went to npm s official website to search for nothing, so I would like to ask if there is a similar f...
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Java.sql.SQLException: Parameter index out of range
Mysql create stored procedure:
create procedure s_add(in a int, in b int, out sum int)
begin
set sum = a + b;
end
After , this is the Java code
package ch04.servlet;
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Ca...
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Does Mysql: if judge whether it is better to write at the business layer or at the database layer?
if in the business layer, within a transaction, there is an if judgment read in the database first, judge according to the result if else, and then read write to the database
and there are if else statements within the mysql database
if you are i...
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What is stored in the database is the html code, how to blur the contents of the query tag?
what is stored in the database is the html code, which is mainly a piece of div content, including the style, does not contain the body and other tags, and the label is strict in opening and closing. If I want to query the keyword "class " now, if I us...
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E-commerce flash sale activity uses Alipay / WeChat Pay
at present, there is a demand. Alipay or Wechat can be used to pay for second-kill merchandise activities, but the problem is that the demand must be paid before deducting inventory, and placing an order does not reduce inventory. In other words, when A...
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Ask questions about push, database, Android
this semester, the teacher gave a project, which is to design a push system. The main function is to realize the function that the server pushes data to the mobile or PC, and the mobile or PC can feedback the data. Because I am a mechanical student, I d...
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Mysql installation here can not go down, how to solve
mysql no compatible servers were found.you ll need to cancel this wizard and insta cannot check.. either ...
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Can I use System.nanoTime () as the primary key ID?
for stand-alone service, the primary key ID is a long integer, which needs to be non-continuous. For example, self-increment cannot be implemented because it is continuous. I thought of using System.nanoTime () to do ID, because I haven t practiced it...
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Data Table Design of like system
how should a like collection system design a data table? I intend to add an array to the user table, put the id of the like content in it, cancel the like, and then remove the id from the array .
find a better way
...
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If you want to randomly query multiple pieces of data, which cannot be repeated each time, how to achieve it?
such as the question: if you want to randomly query multiple pieces of data, which cannot be repeated each time, how to achieve it? ...
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The realization scheme of the top of the article
problem description: a blog system is being developed that needs to achieve the top of an article, and then the foreground will display the article (or more than one) at the top. What I want is to add a new field to determine whether it is a top article...
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Design of user login system
there is such a requirement: user login module, does not support the choice of login method, only a text input box, while supporting: QQ number, mobile number, e-mail, nickname, ID card, etc. (if the user filled in the values of these five fields) any f...
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How to define compound bond in Sequelize?
1:
{
name: A ,
age: 10
}
2:
[{
id:1,
name: A , 1name
book: xxx
},
{
id:2,
name: A ,
book: xxx
}]
name A book are all stored in Table 2. How to deal with a table structure like this?
...
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Now ordinary poker games (such as fighting landlords, Texas hold'em, enough level, etc.), what is used in the background?
1. What kind of record is used in the card game record? I think MongoDB would be better, wouldn t it? 2. Is the logic of playing cards in any language? Is it okay to develop with php ? 3. are the rules of the game and card logic quite difficult? ...
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Are there any good class libraries for Java backup databases (different databases / exports to different formats)? (o (*) o)
for example, the function of backing up the database is encountered in the project, but the database itself is not installed on the machine where the project is running. Is there any good class library you can recommend? (^ ^)
attachment: it is not f...
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After installing mysql through homebrew, why is there no mysql? in the system settings?
...
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How Sequelize saves two tables at a time
as shown in the figure, Table 1 is associated with Table 2. How to click submit and save the two tables together
...
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Hibernate can't save blob when saving it?
mysql database Save the code as follows:
:
...
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How does javascript read the value in the from_unixtime () object? Hurry!
as shown in the figure, if you write x.from_unixtime (xxx,xxx) directly with js, you will report an error directly. how should the value of this object be read? Hurry!
...
