Tag Archives: database

[Solved] Android Room: Database Common Error ‘missing database’

Common error 1:

D:\AndroidProjectsDemo\JetpeckTest\app\build\tmp\kapt3\stubs\debug\com\example\jetpecktest\room\BookDao.
java:15: error: There is a problem with the query: [SQLITE_ERROR] 
SQL error or missing database (no such table: BookEntity)
public abstract java.util.List<com.example.jetpecktest.room.BookEntity> loadAllBooks();

**Solution: * * the error report mentions no such table: bookentity , so first check whether your class is added to the database, that is, check the entities =?In the
annotation in your database class did you add your entity class.

@Database(version = 2, entities = [BookEntity::class])
abstract class DataBase:RoomDatabase() {

Error creating bean with name ‘dataSourceScriptDatabaseInitializer‘ defined in class path resource [

Error creating bean with name ‘dataSourceScriptDatabaseInitializer’ defined in class path resource [org/springframework/boot/autoconfigure/sql/init/DataSourceInitializationConfiguration.class]: Unsatisfied dependency expressed through method ‘dataSourceScriptDatabaseInitializer’ parameter 0; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name ‘dataSource’ defined in class path resource

Error creating bean with name 'dataSourceScriptDatabaseInitializer' defined in class path resource [org/springframework/boot/autoconfigure/sql/init/DataSourceInitializationConfiguration.class]: Unsatisfied dependency expressed through method 'dataSourceScriptDatabaseInitializer' parameter 0; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataSource' defined in class path resource

The reason for my error is that I made an error when using @springboottest automatic injection when I first learned spring data JPA

@SpringBootTest

//springbootTest The server is not turned on by default,

public class MainTest {
    @Autowired
UserRepository userRepository;

@Test
    void t1(){
    System.out.println(userRepository);
}
}

I searched the Internet for several hours and debugged it. I found that the datasource was always empty, because it was tested and run in the test method at that time, and the errors given were always the same as above. However, I clearly configured the database in application.yml, and later found it during overall debugging, Failed to load driver class com.mysql.cj.jdbc.driver in either of hikariconfig class loader or thread context classloader

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.25</version>
        </dependency>

Of course, it may also be due to other errors. If you also encounter this error, you can see whether you have added MySQL dependencies to your dependencies

[Solved] mysqldump: Error: ‘Access denied; you need (at least one of) the PROCESS privilege(s) for this opera

Problem: back up the database on centos7 of the virtual machine, and an error occurs when executing mysqldump: error: ‘access denied; You need (at least one of) the process privilege (s) for this operation ‘when trying to dump tablespaces

[root@localhost backup]# sh ./mysql_backup.sh
Start exporting the database...
mysqldump: Error: 'Access denied; you need (at least one of) the PROCESS privilege(s) for this operation' when trying to dump tablespaces
The export was successful and the file name is : /data/backup/mysql/2021-10-06_003536.sql.gz

Solution: log in to MySQL with the root account in CentOS

[root@localhost backup]# mysql -uroot -p

Input password

Then execute the command

mysql> GRANT PROCESS ON *.* TO 'demo'@'localhost';

This demo should be changed to your own login database account

Then refresh the database

mysql> flush privileges;

All execution processes:

[root@localhost backup]# mysql -uroot -p
Enter password: 
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 61
Server version: 8.0.24 Source distribution

Copyright (c) 2000, 2021, Oracle and/or its affiliates.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> GRANT PROCESS ON *.* TO 'demo'@'localhost';
Query OK, 0 rows affected (0.01 sec)

mysql> flush privileges;
Query OK, 0 rows affected (0.01 sec)

mysql> exit
Bye
[root@localhost backup]# sh ./mysql_backup.sh
Start exporting the database... 
The export was successful and the file name is : /data/backup/mysql/2021-10-06_003815.sql.gz
[root@localhost backup]#

This method is accessed locally by the user

Another method is to change localhost to% by using the global access command

mysql> GRANT PROCESS ON *.* TO 'demo'@'%';

Similarly, change the demo to your own MySQL login account, and then execute the above command to refresh the database

I used the first method.

[Solved] Request.url is not modifiable, use Request.replace() instead

Encountered in a scene_ In the redis project, the URL needs to be filtered and de duplicated, so a de duplication class is customized

Simply copy the source code directly, and then rewrite the request_ See, to change the logic, the original direct assignment will report the error of the title

    def request_seen(self, request):
        temp_request = request
        if "ref" in temp_request.url:
            # An error is reported here, you cannot assign a value directly
            temp_request.url = temp_request.url.split("ref")[0]
        fp = self.request_fingerprint(temp_request)
        added = self.server.sadd(self.key, fp)
        return added == 0

Solution:

Use _set_URL (URL) is OK

temp_request._set_url(temp_request.url.split("ref")[0])

The complete code is as follows:

from scrapy.dupefilters import BaseDupeFilter
from scrapy.utils.request import request_fingerprint
from scrapy_redis import get_redis_from_settings
from scrapy_redis import defaults
import logging
import time

logger = logging.getLogger(__name__)


class UrlFilter(BaseDupeFilter):
    logger = logger

    def __init__(self, server, key, debug=False):
        self.server = server
        self.key = key
        self.debug = debug
        self.logdupes = True

    @classmethod
    def from_settings(cls, settings):
        server = get_redis_from_settings(settings)
        # XXX: This creates one-time key. needed to support to use this
        # class as standalone dupefilter with scrapy's default scheduler
        # if scrapy passes spider on open() method this wouldn't be needed
        # TODO: Use SCRAPY_JOB env as default and fallback to timestamp.
        key = defaults.DUPEFILTER_KEY % {'timestamp': int(time.time())}
        debug = settings.getbool('DUPEFILTER_DEBUG')
        return cls(server, key=key, debug=debug)

    @classmethod
    def from_crawler(cls, crawler):
        """Returns instance from crawler.

        Parameters
        ----------
        crawler : scrapy.crawler.Crawler

        Returns
        -------
        RFPDupeFilter
            Instance of RFPDupeFilter.

        """
        return cls.from_settings(crawler.settings)

    def request_seen(self, request):
        temp_request = request
        if "ref" in temp_request.url:
            temp_request._set_url(temp_request.url.split("ref")[0])
        fp = self.request_fingerprint(temp_request)
        added = self.server.sadd(self.key, fp)
        return added == 0

    def request_fingerprint(self, request):
        """Returns a fingerprint for a given request.

        Parameters
        ----------
        request : scrapy.http.Request

        Returns
        -------
        str

        """
        return request_fingerprint(request)

    @classmethod
    def from_spider(cls, spider):
        settings = spider.settings
        server = get_redis_from_settings(settings)
        dupefilter_key = settings.get("SCHEDULER_DUPEFILTER_KEY", defaults.SCHEDULER_DUPEFILTER_KEY)
        key = dupefilter_key % {'spider': spider.name}
        debug = settings.getbool('DUPEFILTER_DEBUG')
        return cls(server, key=key, debug=debug)

    def close(self, reason=''):
        """Delete data on close. Called by Scrapy's scheduler.

        Parameters
        ----------
        reason : str, optional

        """
        self.clear()

    def clear(self):
        """Clears fingerprints data."""
        self.server.delete(self.key)

    def log(self, request, spider):
        """Logs given request.

        Parameters
        ----------
        request : scrapy.http.Request
        spider : scrapy.spiders.Spider

        """
        if self.debug:
            msg = "Filtered duplicate request: %(request)s"
            self.logger.debug(msg, {'request': request}, extra={'spider': spider})
        elif self.logdupes:
            msg = ("Filtered duplicate request %(request)s"
                   " - no more duplicates will be shown"
                   " (see DUPEFILTER_DEBUG to show all duplicates)")
            self.logger.debug(msg, {'request': request}, extra={'spider': spider})
            self.logdupes = False

Bulk Update Error: #Cause: java.sql.SQLSyntaxErrorException: You have an error in your SQL syntax； check the m

Error:
mybatis plus foreach batch insert is OK. Change it to update and keep reporting errors. It is OK to copy the SQL and execute it separately.
reason:
the insert statement supports batch and can be written in one statement:

INSERT INTO table_name (column1,column2,column3,...) VALUES (value1,value2,value3,...), (value1,value2,value3,...), (value1,value2,value3,...), (value1,value2,value3,...), (value1,value2,value3,...),(value1,value2,value3,...)；

Update does not support batch. There are multiple statements corresponding to cyclic batch

update table set c1=v1;
update table set c1=v2;
update table set c1=v3;
.
.
.
update table set c1=v...;

Mybatis does not support executing multiple statements (multiple semicolons) by default
solution:
add the allowmultiqueries = true parameter to the database connection

Allowmultiqueries = true function:
1. You can carry semicolons after SQL statements to realize multi statement execution
2. You can execute batch processing and issue multiple SQL statements at the same time

[Solved] Error: ER_HOST_NOT_PRIVILEGED: Host ‘x.x.x.x‘ is not allowed to connect to this MySQL server

Problem Description:

Use nodejs to connect to the MySQL database of ECs and execute the JS file. The error is as follows:

Error: ER_HOST_NOT_PRIVILEGED: Host 'x.x.x.x' is not allowed to connect to this MySQL server
{
  code: 'ER_HOST_NOT_PRIVILEGED',
  errno: 1130,
  sqlMessage: "Host 'x.x.x.x' is not allowed to connect to this MySQL server",
  sqlState: undefined,
  fatal: true
}

Solution:

This is caused by MySQL configuration that does not support remote connection. You need to connect to the server for the following configuration (log in to the root account):

mysql -u root -p
use mysql;
select host from user where user='root';
update user set host = '%' where user ='root';
// If Host = '%', it means that all IPs have connection privileges, which should be set according to the IPs of the production environment
flush privileges;

CLP: error: getaddrinfo enotfound http://x.x.x.x/

Problem Description:

Use nodejs to connect to the MySQL database of ECs and execute the JS file. The error is as follows:

Error: getaddrinfo ENOTFOUND http://x.x.x.x/
{
  errno: -3008,
  code: 'ENOTFOUND',
  syscall: 'getaddrinfo',
  hostname: 'http://x.x.x.x/',
  fatal: true
}

resolvent:

In the createconnection method, the host can write the domain name or server IP address

Error creating bean with name ‘lettuceClientResources‘ defined in class path resource

Error message

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'lettuceClientResources' defined in class path resource [org/springframework/boot/autoconfigure/data/redis/LettuceConnectionConfiguration.class]: Bean instantiation via factory method failed; ....

You can see that redis appears in the message. The reason for my error is that the dependency of spring boot starter data redis is added to the pom.xml file, but the redis connection information is not configured.

How to Solve Sqlyog error 2058

Sqlyog configures a new connection and reports an error: the error number is 2058. It is analyzed that the MySQL password encryption method has changed
solution:
alter user ‘root’ @ ‘localhost’ identified with MySQL_ native_ password BY ‘password’; (note the semicolon)
#password is the root password you set yourself

after reconfiguring the connection of sqlyog, the connection is successful and it is OK.

Redis Cluster Error: (error) CLUSTERDOWN Hash slot not served

Redis cluster error clusterdown hash slot not served

Just yesterday, I configured the redis cluster, but when I went to restart today, the redis cluster reported an error clusterdown hash slot not served. I checked the Internet and didn’t solve it
finally, just delete the nodesxxxx.conf and xxxx.aof files. I think it is caused by the AOF cache of redis
after deletion.