$check = $connect->execute("SELECT * FROM information_schema.schemata WHERE schema_name='".$database."'"); if (!$check && !$connect->execute("CREATE DATABASE IF NOT EXISTS `".$database."` default collate utf8_general_ci ")) { return resultArray(['error' => '没有找到您填写的数...
在MySQL中,我们可以使用IF EXISTS子句来判断数据库是否存在。这样,如果数据库存在,就执行某个操作;否则,就不执行。 以下是一个使用IF EXISTS子句的示例: IFEXISTS(SELECTSCHEMA_NAMEFROMINFORMATION_SCHEMA.SCHEMATAWHERESCHEMA_NAME='mydatabase')SELECT'Database exists.';ELSESELECT'Database does not exist.'; 1....
Therefore, we can check the exit status for determining whether the database exists or not in a shell script: $ result=$(mysql -u user -e "use students") $ if [[ $result -eq 0 ]] then echo "The database exists" else echo "The database doesn’t exist" fi 2.2. Using the show...
"Can't create database '%-.64s' (errno: %d)", #define ER_DB_CREATE_EXISTS 1007 "Can't create database '%-.64s'; database exists", #define ER_DB_DROP_EXISTS 1008 "Can't drop database '%-.64s'; database doesn't exist", #define ER_DB_DROP_DELETE 1009 "Error dropping data...
Date: July 22, 2010 06:09AM Hello! I am writing a python function to check if a user exists in a database. This is the code: def searchUser(): print 'Which user are you looking for?' Username = raw_input('> ') sql = '''IF EXISTS (SELECT * FROM Users WHERE Username = %s...
15、显示use的数据库名: mysql> SELECT DATABASE(); 16、显示当前的user: mysql> SELECT USER(); 三、一个建库和建表以及插入数据的实例 drop database if exists school; //如果存在SCHOOL则删除 create database school; //建立库SCHOOL use school; //打开库SCHOOL create table teacher //建立表TEACHER...
1 . 数据库创建 : Create database db_name; 数据库删除 : Drop database db_name; 删除时可先判断是否存在,写成 : drop database if exits db_name 2 . 建表 : 创建数据表的语法 : create table table_name (字段1 数据类型 , 字段2 数据类型); ...
c# Check registry if program is installed if yes get install location ? C# Check to make sure first character in a string is a letter C# check username if already exists from database C# Class - USB Port Enabled/Disabled Status Detection C# class for JSON is resulting a Null Reference Exc...
mysql>CREATE{DATABASE|SCHEMA}[IF NOT EXISTS]db_name[DEFAULT][CHARACTERSET=''][DEFAULT][COLLATE=''] 1. 示例如下: 删除数据库 DROP{DATABASE|SCHEMA}[IF EXISTS]db_name 1. 示例如下: 修改数据库 ALTER{DATABASE|SCHEMA}db_name[DEFAULT][CHARACTERSET=''][DEFAULT][COLLATE=''] ...
2. You have specified the wrong database in your connection string - you need to specify the database in the connection string where "table" in your query exists, otherwise the query is failing. 3. You have an error in your query, do you have the correct table and column names? Se...