Common library operations:
- Create a database CREATE DATABASE database name;
- delete the database DROP DATABASE database name;
- displays all databases: SHOW DATABASES;
Common Table Operations:
- Create table: CREATE TABLE table name (attribute name Data type [integrity constraints],
property name data type [integrity constraint],
.
.
Attribute name data table [integrity constraints]
);
| Restrictions | Explanation |
| PRIMARY KEY | Attribute that identifies the primary key of the table, the unique identifier corresponding to the record |
| FOREIGN KEY | Attribute that identifies the foreign key table, associated with the primary key of a table |
| NOT NULL | It identifies the property can not be empty |
| UNIQUE | Identification value of this property is unique |
| AUTO_INCREMENT | It identifies the attribute value is automatically increased |
| DEFAULT | The default value for this property is set |
- Table View
| operating | Statement |
| View basic table structure | DESCRIBE (or DESC) table name; // return table fields and their details table |
| View detailed structure of the table | SHOW CREATE TABLE table name; // return the result is to create a table of sql |
- Delete table
| Statement | meaning |
| drop table 表名； | Completely remove the table, delete the field data, free up memory space |
| truncate 表名； | Delete table data, do not delete the field, free up memory space |
| delete from table name; or delete * from table name; | Remove content does not delete the definition, not free up space, delete the system line by line, lower efficiency than truncate |
** truncate and delete contrast: **
TRUNCATE will reset the line and all the high level of the index. When the entire table and index complete browse through the table after the operation than truncate table after the Delete operation much faster. When the table is emptied of the index table and the table is reset to the initial size, but can not delete.
truncate is implicit submission, you can not trigger any Delete triggers rollback command can not be withdrawn, and can delete, delete statement line because each deletion, are recorded one for each row deleted in the transaction log;
truncate function in the Table on a delete statement with no WHERE clause is the same: both remove all rows in the table. But truncate delete faster than the speed, and low system resource usage and transaction logs, because delete is to delete the line by line.
Note: truncate can not empty the parent table
- Modify table
| operating | Statement |
| Modify the table name | ALTER TABLE table name RENMAE new table the old name; |
| Modify the field | ALTER TABLE table name CHANGE old name for the new property attribute names new data types |
| Increase the field | ALTER TABLE table name ADD attribute name Data type [integrity constraints] |
| Delete field | ALTER TABLE table DROP attribute name |
- insert data
| operating | Statement |
| All fields of the table to insert data | INSERT INTO table name VALUES (value 1, value 2 and value 3, ..., n-value); |
| Inserted to the specified fields of the table data | INSERT INTO table name (attribute 1, property 2, ..., attributes n) VALUES (value 1, value 2 and value 3, ..., n-value); |
| Simultaneously insert multiple records | INSERT INTO table name [(attribute list)] the VALUES (argument list 1), (2 argument list) ..., (n-value list); |
- update data
SET UPDATE table name attribute value 1 = 1, attribute name = value 2 2, ..., n = attribute name value n WHERE conditional expression;
- delete data
DELETE FROM table [WHERE conditional expression]
Left a large piece of inquiry, to be updated! ! !