no database selected

1, first put aside Mycat to deal with2. When querying a table, specify which database to be, and then query.①, if the MySQL Workbench is used first, use TableName, and then execute the action statement, or specify the database select * from

I'm just learning to use PDO to manipulate the database, but, after connecting to the database, use Query () to execute the SELECT query statement, but always error: No database selected, code and error information as follows: setattribute

Theoretical basisDatabase server is one of the most widely used server types, and many enterprises have to purchase database server in the process of informatization construction. Database server is mainly used for storing, querying and retrieving

BackgroundRecently, @ alizhengxiang (teacher Yang) posted a microblog on the top. Who knows, Shi has stirred up waves and friends from various database fields in China have posted a few new topics on this microblog, both radical debate and attack

Issue: The schemas bar displays "No Object selected" When you select a database on a Mac using MySQL Workbench. Processing: Close Workbench Open terminal, reset software configuration 路径：--Maccd ~/Library/Application\

Mssqlserver backup restoration method full backup: backs up all selected folders and does not rely on the file archive attribute to determine which files to back up. (During the backup process, any existing tags are cleared, and each file is marked

4. What are the categories of computers? What are their characteristics?Traditionally, there are three types: Large hosts, minicomputers, and minicomputers. Large hosts are generally high-performance parallel processing systems with large storage

[[Email protected] ~] $! SQLSqlplus/As sysdba SQL * Plus: Release 11.2.0.1.0 production on Wed Aug 27 09:50:54 2014 Copyright (c) 1982,200 9, Oracle. All rights reserved. Connected:Oracle Database 11g Enterprise Edition Release 11.2.0.1.0-64bit

Oracle9i Database Data guard implementation and maintenance manual By kamus I.Data guardIntroduction Standby database is a high availability (High Available) number launched by Oracle. The data warehouse solution ensures Data Synchronization Through

8.3 Managing Primary Database Events That Affect the Standby Database8.3 Managing the master Database can Affect the Events of the slave Database To prevent possible problems, you must be aware of events on the primary database that affect a standby