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Glossary of Common SQL Statements
ALTER DATABASE
ALTER DATABASE database_name;
ALTER DATABASE command changes the size or settings of a database. Its syntax
澳洲指导ASSIGNMENT varies widely among different database systems.
ALTER USER
ALTER USER user
ALTER USER statement changes a user's system settings such as password.
BEGIN TRANSACTION
1> BEGIN TRANSACTION transaction_name
2> transaction type
3> if exists
4> begin
BEGIN TRANSACTION statement signifies the beginning of a user transaction. A
transaction ends when it is either committed (see COMMIT TRANSACTION) or canceled
(see ROLLBACK TRANSACTION). A transaction is a logical unit of work.
CLOSE CURSOR
close cursor_name
CLOSE cursor_name statement closes the cursor and clears it of data. To completely
remove the cursor, use the DEALLOCATE CURSOR statement.
COMMIT TRANSACTION
SQL> COMMIT;
COMMIT TRANSACTION statement saves all work begun since the beginning of the
transaction (since the BEGIN TRANSACTION statement was executed).
CREATE DATABASE
SQL> CREATE DATABASE database_name;
database_name creates a new database. Many different options can be supplied, such
as the device on which to create the database and the size of the initial database.
CREATE INDEX
CREATE INDEX index_name
ON table_name(column_name1, [column_name2], ...);
the contents of the indexed field(s).
CREATE PROCEDURE
create procedure procedure_name
[[(]@parameter_name
datatype [(length) | (precision [, scale])
[= default][output]
[, @parameter_name
datatype [(length) | (precision [, scale])
[= default][output]]...[)]]
[with recompile]
as SQL_statements
CREATE PROCEDURE statement creates a new stored procedure in the database. This
stored procedure can consist of SQL statements and can then be executed using the
EXECUTE command. Stored procedures support input and output parameters passing
and can return an integer value for status checking.
CREATE TABLE
CREATE TABLE table_name
( field1 datatype [ NOT NULL ],
field2 datatype [ NOT NULL ],
field3 datatype [ NOT NULL ]...)
CREATE TABLE statement creates a new table within a database. Each optional field is
provided with a name and data type for creation within that table.
CREATE TRIGGER
create trigger trigger_name
on table_name
for {insert, update, delete}
as SQL_Statements
CREATE TRIGGER statement creates a trigger object in the database that will execute
its SQL statements when its corresponding table is modified through an INSERT,
UPDATE, or DELETE. Triggers can also call stored procedures to execute complex tasks.
CREATE USER
CREATE USER user#p#分页标题#e#
CREATE USER statement creates a new user account complete with user ID and
password.
CREATE VIEW
CREATE VIEW <view_name> [(column1, column2...)] AS
SELECT <table_name column_names>
FROM <table_name>
using the CREATE VIEW statement. After a view is created, it can be queried and data
within the view can be modified.
DEALLOCATE CURSOR
deallocate cursor cursor_name
DEALLOCATE CURSOR statement completely removes the cursor from memory and
frees the name for use by another cursor. You should always close the cursor with the
CLOSE CURSOR statement before deallocating it.
DECLARE CURSOR
declare cursor_name cursor
for select_statement
DECLARE CURSOR statement creates a new cursor from the SELECT statement query.
The FETCH statement scrolls the cursor through the data until the variables have been
loaded. Then the cursor scrolls to the next record.
DROP DATABASE
DROP DATABASE database_name;
DROP DATABASE statement completely deletes a database, including all data and the
database's physical structure on disk.
DROP INDEX
DROP INDEX index_name;
DROP INDEX statement removes an index from a table.
DROP PROCEDURE
drop procedure procedure_name
DROP PROCEDURE statement drops a stored procedure from the database; its function is
similar to the DROP TABLE and DROP INDEX statements.
DROP TABLE
DROP TABLE table_name;
DROP TABLE statement drops a table from a database.
DROP TRIGGER
DROP TRIGGER trigger_name
DROP TRIGGER statement removes a trigger from a database.
DROP VIEW
DROP VIEW view_name;
DROP VIEW statement removes a view from a database.
EXECUTE
execute [@return_status = ]
procedure_name
[[@parameter_name =] value |
[@parameter_name =] @variable [output]...]]
EXECUTE command runs a stored procedure and its associated SQL statements.
Parameters can be passed to the stored procedure, and data can be returned in these
parameters if the output keyword is used.
FETCH
fetch cursor_name [into fetch_target_list]
FETCH command loads the contents of the cursor's data into the provided program
variables. After the variables have been loaded, the cursor scrolls to the next record.
FROM
FROM <tableref> [, <tableref> ...]
FROM specifies which tables are used and/or joined.
GRANT
GRANT role TO user
or
GRANT system_privilege TO {user_name | role | PUBLIC}
GRANT command grants a privilege or role to a user who has been created using the
CREATE USER command.
GROUP BY
GROUP BY <col> [, <col> ...]
GROUP BY statement groups all the rows with the same column value.
HAVING
HAVING <search_cond>
HAVING is valid only with GROUP BY and limits the selection of groups to those that#p#分页标题#e#
satisfy the search condition.
INTERSECT
INTERSECT
INTERSECT returns all the common elements of two SELECT statements.
ORDER BY
ORDER BY <order_list>
ORDER BY statement orders the returned values by the specified column(s).
ROLLBACK TRANSACTION
ROLLBACK TRANSACTION statement effectively cancels all work done within a
transaction (since the BEGIN TRANSACTION statement was executed).
REVOKE
REVOKE role FROM user;
or
REVOKE {object_priv | ALL [PRIVILEGES]}
[, {object_priv | ALL [PRIVILEGES]} ] ...
ON [schema.]object
FROM {user | role | PUBLIC} [, {user | role | PUBLIC}] ...
澳洲指导ASSIGNMENTREVOKE command removes a database privilege from a user, whether it be a system
privilege or a role.
SELECT
SELECT [DISTINCT | ALL]
SELECT statement is the beginning of each data retrieval statement. The modifier
DISTINCT specifies unique values and prevents duplicates. ALL is the default and
allows duplicates.
SET TRANSACTION
SQL> SET TRANSACTION (READ ONLY | USE ROLLBACK SEGMENT);
SET TRANSACTION enables the user to specify when a transaction should begin. The
READ ONLY option locks a set of records until the transaction ends to ensure that the
data is not changed.
UNION
UNION
UNION statement returns all the elements of two SELECT statements.
WHERE
WHERE <search_cond>
澳洲指导ASSIGNMENTWHERE statement limits the rows retrieved to those meeting the search condition.
*
* gets all the columns of a particular table.
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