ddl dml dcl

database users and roles.Grant, authorization;REVOKE, recycling Authority;Summary: In a nutshell, DML (Data Manipulation language) is the language that operates on the contents of the data, and its smallest operating unit is the line;The DDL (data definition Language) is the language that operates on data objects and object properties, and its operation alters data properties such as table structure, table

Second, the SQL languageSQL structure Query Language structured queries languageSQL statement: DDL statement DML statement, DCL statementDdl--data define language--create, alter, drop-data definition languageDml--data Management language--insert, UPDATE, delete--Data manipulation languageDcl--data Control Language--grant, revoke--Data Control languageIntroduction

Tags: data revoke back LTE database base program Rollback POI1.DDL (data definition Language) database definition language: DDL gives us the ability to create or delete tables. You can define indexes (keys), specify links between tables, and impose constraints between tables.? Common DDL Statements:–create database (creating new databases)–alter database (modifyi

are indirectly completed with SQL commands are implicitly committed. These commands are:Alter,audit,comment,connect,create,disconnect,drop,Exit,grant,noaudit,quit,revoke,rename.(3) Automatic submissionIf the autocommit is set to ON, after the insert, modify, DELETE statement executes,The system will commit automatically, which is automatic submission. The format is:Sql>set autocommit on;2) Savepoint-identify a point in a transaction-which can later roll back SavePoint3) Rollback-restore databas

Label:The difference between DML, DDL, DCL1. DML Overview: (Data manipulation language), manipulation language. Used to manipulate the data contained in a database object, which means that the manipulated object is a record.1.1 The main statement of DML (that is, the action statement)Insert statement: Inserts a record

|default|extra| +--------+------------+------+-----+---------+-------+ |name|char () |NO||NULL| | |age|tinyint (4) |YES ||NULL| | |course|char (+) |yes|| null|| +--------+------------+------+-----+---------+-------+ 3rowsinset (0.00sec) Insert data into the newly created table in the format insert into Tb_name (col1,col2,...) VALUES (Value1,value2 ...); You can insert one field at a time, and if all the fields are inserted, the (NAME) can be omitted. mysql[test]>insertintostudents (NAME) VALUES

You can take a look at this Weibo blog: http://blog.csdn.net/jiben2qingshan/article/details/7832344http://blog.163.com/chenwenlin_89/blog/static/135159174201011295818330/The DDL (data definition Language) is used to manipulate the properties of objects and objects, including the database itself, as well as database objects, such as tables, views, and so on, and the DDL's management and definition of these objects and properties are represented in the

General Explanation:DML (Data Manipulation language):They are select, UPDATE, INSERT, DELETE, just like its name, these 4 commands are the languages used to manipulate the data in the databaseDDL (data definition Language):DDL is more than DML, the main command has create, alter, DROP, etc., DDL is mainly used in the definition or Change tables (table) of the str

during the INSERT operation, which causes Oracle to recursively clear the recycle bin. This operation is DDL. As a result, there is a problem at the beginning. Of course, this problem does not occur in a well-monitored production environment. When the tablespace is insufficient, the monitoring system should first trigger an alarm. However, the test shows that the space of the deleted table is calculated as the space remaining in the tablespace. If

COMMIT : Permanently saves modifications to the database in the transaction. Explicit commit: The SQL statement needs to be actively submitted for database modifications, which can be rollback before being committed. such as DML operations. Implicit commit: The SQL statement execution ends Autocommit and cannot be rollback. such as DDL,DCL. Rol

remaining in the tablespace. If the recycle bin is opened, even if the system seems to have dozens of GB remaining, the space may be the space of the table to be deleted. You need to clear the recycle bin to use it. If the ddl trigger exists in the system, it may cause that there is a lot of available space in the system, but INSERT reports the error "ORA-234567, do not allow the development to execute DDL