To change the structure of a table you use ALTER TABLE statement. This allows you to add or drop column, change data type, rename table etc. Example of ALTER TABLE: ALTER TABLE table_name CHANGE COLUMN table_id table_id INT(11) NOT NULL AUTO_INCREMENT; To remove existing table you need to use DROP TABLE statement as below: Example […]
A primary key is a column or multiple columns that uniquely identify each row in a table. Basic key of primary key: – This must contain unique values – For multiple columns, the combination of values must be unique – Primary key is not null – Only one primary key will be present in a […]
Using CREATE TABLE statement in MySQL you can create a table into the database. The following example shows the statement in the simple form: CREATE TABLE Format: CREATE TABLE IF NOT EXISTS `tbl` ( tbl_id int(11) NOT NULL AUTO_INCREMENT, tbl_title varchar(100) DEFAULT NULL, post_date DATE DEFAULT NULL, update_date DATE DEFAULT NULL, PRIMARY KEY (tbl_id) ) […]
When you create a database you have to choose the storage engine for storing data into the database. MySQL supports various types of storage engines i.e. MyISAM, InnoDB, MERGE, MEMORY (HEAP), ARCHIVE, CSV, FEDERATED. Each storage engines has different performance of the database and has advantages or disadvantages. Here is the list of MySQL Storage […]
Want to store IP addresses in database and still using VARCHAR(15)? You can actually store IP addresses as integer values because using INT you go down to 4 bytes of space and have a fixed size field. As the range of a IP Addresses are 32 bit unsigned integer you can use your column as […]
First of all think whether you require a NULL field or not.If having an empty string value can make any sense then use it otherwise use NULL value for a specific reason. So, Put NOT NULL if required. NULL columns require additional space in the row and add complexity to your statement. Avoid it for […]
If you want to analyze the columns structures of a MySQL table and want to view the actual data in your table with certain suggestion then you can get help from PROCEDURE ANALYSE(). For example, if any data present in your table and plays a big role in any decision making then this is very […]
MyISAM vs Innodb – both are commonly used engines on MySQL servers and they both have their unique advantages and disadvantages against each other. MyISAM is the default storage engine type for MySQL 5.0 but the Cloud Sites environment defaults the storage engine to Innodb. MyISAM vs Innodb: MyISAM: Table level locking. Innodb: Row level […]
It is relational database concept in which multiple tables shares consistent relationship based on the data stored on tables. For example, a school X has 2 tables, a student table, and a student fee table. In the student table we have 2 columns – the student ID and the student name. In the student fee […]
For improving the speed of operation in a table we use MySQL INDEX. We can create more than one field as a index field in a table. This is basically use for searching process so that it can lookup records very fast. As it fetches record very fast from the database, during insert and update […]