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MySQLi Articles
Page 330 of 341
Populating a table from query results in MySQL?
To populate a table from query results, use the following syntax:INSERT yourTableName(yourColumnName1, yourColumnName2, yourColumnName3, ..........N) SELECT yourColumnName1, yourColumnName2, yourColumnName3, ..........N FROM yourAnotherTableName;To understand the above syntax, let us create a table. The first table is as follows with some records. The query to create a table is as follows:mysql> create table PopulateTableDemo -> ( -> Id int NOT NULL AUTO_INCREMENT, -> Name varchar(20), -> Amount int, -> ArrivalDateTime datetime, -> PRIMARY KEY(Id) -> ); Query OK, 0 rows affected (0.68 sec)Now you can insert some records in the table using insert command. The ...
Read MoreShortcomings of mysql_real_escape_string?
The shortcoming of mysql_real_escape_string is as follows − It has main shortcoming in the modern API while we are making prepared statement. This has another shortcoming for every possible attack when you will typecast. Let us see the typecast syntax in MySQL − (TypeCast)mysql_real_escape_string($_REQUEST['anyColumnName'])); In the above syntax, we are typecasting, but in this case, it is not safer for every possible attack. The other cases include the following − It is not type safe. It is not for injection attack.
Read MoreHow to add super privileges to MySQL database?
Firstly, check the MySQL database with DESC command. mysql>DESC mysql.db; The following is the output. +-----------------------+---------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +-----------------------+---------------+------+-----+---------+-------+ | Host | char(60) | NO | PRI | | ...
Read MoreIs the primary key automatically indexed in MySQL?
Yes, primary key is automatically indexed in MySQL because primary key, index, etc gets stored into B-trees. All engines including InnoDB as well as MyISAM automatically supports the primary key to be indexed. The primary key is implicitly indexed in InnoDB, MyISAM, and other engines. Let us create a table with primary key − mysql> create table DemoIndex -> ( -> Id int not null, -> primary key(Id) -> ); Query OK, 0 rows affected (1.21 sec) In the above table, Id is implicitly indexed.
Read MoreHow to disable ONLY_FULL_GROUP_BY in MySQL?
You can enable ONLY_FULL_GROUP_BY in MySQL as shown in the following query − mysql> SET sql_mode = 'ONLY_FULL_GROUP_BY'; Query OK, 0 rows affected (0.01 sec) As shown above, we can enable ONLY_FULL_GROUP_BY with the help of SET command. To disable ONLY_FULL_GROUP_BY with the help of the following query − mysql> SET GLOBAL sql_mode=(SELECT REPLACE(@@sql_mode,'ONLY_FULL_GROUP_BY','')); Query OK, 0 rows affected (0.04 sec) We have disabled ONLY_FULL_GROUP_BY successfully.
Read MoreHow to take backup of a single table in a MySQL database?
The backup of a table can be made with the help of backup table as well as mysqldump utility. The backup table concept was used in MySQL version 5.0 and its earlier version. Here, I am performing backup with the help of mysqldump. Firstly, we will open cmd with the help of shortcut key. The mysqldump will run at the cmd. Therefore, firstly open cmd with the help of shortcut key − windowskey+R; Here is the snapshot − Now, cmd will open − In this, the MySQL bin folder is present at the following location − ...
Read MoreERROR 1396 (HY000): Operation CREATE USER failed for 'root'@'localhost'?
In the system, the root is defined by another name as well as password. Then the user is created as a root with the help of the create command. This will result in the ERROR 1396. The query for this is given as follows − mysql> create user 'root'@'localhost' identified by 'root123'; After executing the above query, the following error is obtained − ERROR 1396 (HY000): Operation CREATE USER failed for 'root'@'localhost' The user can be created with another name and password successfully. This is given as follows − mysql> create user 'John'@'localhost' identified by ...
Read MoreAdvantages of using MySQLi over MySQL?
MySQLi is also known as MySQL improved Extension. It is a relational SQL database management system. It is often used inside PHP to provide an interface with the MySQL databases. Some of the reasons why MySQLi is famous are given below − MySQLi uses the standard form of the SQL language. MySQLi is free as it is released under an open source license. MySQLi can be easily used with PHP which is the most famous language for web development. MySQLi is a very powerful language and it can handle the functionality of powerful database packages. MySQLi can work with ...
Read MoreWhich one is preferred between a large table or multiple small tables in MySQL?
It is very difficult to say whether to prefer one large table or multiple small tables. It depends − On the application we are using. On database normalization However, there are many key points, through which we can say that multiple small tables are good in that situation. Suppose many developers are going to develop multiple tables, then there is a need to split them into multiple small tables. A situation when you are giving authority to many developers. This authority is for different parts of data. In this case, a need arise to split into multiple small ...
Read MoreOpen MySQL root access from all hosts?
To open root access from all hosts, we need to change the database to “mysql” with the help of USE command. The syntax of USE command is as follows − USE anyDatabasename; Now, I will use predefined database ‘mysql’, which is as follows − mysql> use mysql; Database changed I have changed the database above. Here is the query to get root access from the entire host − mysql> UPDATE user set host='%' where host='localhost'; Query OK, 6 rows affected (0.19 sec) Rows matched: 6 Changed: 6 Warnings: 0
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