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结构定义
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CREATE TABLE
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创建新表。
语法：
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sql-command ::=
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CREATE [TEMP | TEMPORARY] TABLE table-name (
column-def [, column-def]*
[, constraint]*
)
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sql-command ::=
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CREATE [TEMP | TEMPORARY] TABLE [database-name.] table-name AS select-statement
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column-def ::=
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name [type] [[CONSTRAINT name] column-constraint]*
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type ::=
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typename |
typename ( number ) |
typename ( number , number )
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column-constraint ::=
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NOT NULL [ conflict-clause ] |
PRIMARY KEY [sort-order] [ conflict-clause ] |
UNIQUE [ conflict-clause ] |
CHECK ( expr ) [ conflict-clause ] |
DEFAULT value |
COLLATE collation-name
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constraint ::=
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PRIMARY KEY ( column-list ) [ conflict-clause ] |
UNIQUE ( column-list ) [ conflict-clause ] |
CHECK ( expr ) [ conflict-clause ]
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conflict-clause ::=
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ON CONFLICT conflict-algorithm
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CREATE VIEW
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创建一个视图（虚拟表），该表以另一种方式表示一个或多个表中的数据。
语法：
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sql-command ::=
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CREATE [TEMP | TEMPORARY] VIEW [database-name.] view-name AS select-statement
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例子：
CREATE VIEW master_view AS
SELECT * FROM sqlite_master WHERE type='view';
说明：
创建一个名为master_view的视图，其中包括sqlite_master这个表中的所有视图表。
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CREATE TRIGGER
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创建触发器，触发器是一种特殊的存储过程，在用户试图对指定的表执行指定的数据修改语句时自动执行。
语法：
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sql-statement ::=
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CREATE [TEMP | TEMPORARY] TRIGGER trigger-name [ BEFORE | AFTER ]
database-event ON [database-name .] table-name
trigger-action
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sql-statement ::=
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CREATE [TEMP | TEMPORARY] TRIGGER trigger-name INSTEAD OF
database-event ON [database-name .] view-name
trigger-action
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database-event ::=
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DELETE |
INSERT |
UPDATE |
UPDATE OF column-list
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trigger-action ::=
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[ FOR EACH ROW | FOR EACH STATEMENT ] [ WHEN expression ]
BEGIN
trigger-step ; [ trigger-step ; ]*
END
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trigger-step ::=
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update-statement | insert-statement |
delete-statement | select-statement
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例子：
CREATE TRIGGER update_customer_address UPDATE OF address ON customers
BEGIN
UPDATE orders SET address = new.address WHERE customer_name = old.name;
END;
说明：
创建了一个名为update_customer_address的触发器，当用户更新customers表中的address字段时，将触发并更新orders表中的address字段为新的值。
比如执行如下一条语句：
UPDATE customers SET address = '1 Main St.' WHERE name = 'Jack Jones';
数据库将自动执行如下语句：
UPDATE orders SET address = '1 Main St.' WHERE customer_name = 'Jack Jones';
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CREATE INDEX
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为给定表或视图创建索引。
语法：
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sql-statement ::=
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CREATE [UNIQUE] INDEX index-name
ON [database-name .] table-name ( column-name [, column-name]* )
[ ON CONFLICT conflict-algorithm ]
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column-name ::=
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name [ COLLATE collation-name] [ ASC | DESC ]
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例子：
CREATE INDEX idx_email ON customers (email);
说明：
为customers表中的email创建一个名为idx_email的字段。
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结构删除
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DROP TABLE
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删除表定义及该表的所有索引。
语法：
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sql-command ::=
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DROP TABLE [database-name.] table-name
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例子：
DROP TABLE customers;
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DROP VIEW
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删除一个视图。
语法：
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sql-command ::=
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DROP VIEW view-name
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例子：
DROP VIEW master_view;
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DROP TRIGGER
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删除一个触发器。
语法：
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sql-statement ::=
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DROP TRIGGER [database-name .] trigger-name
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例子：
DROP TRIGGER update_customer_address;
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DROP INDEX
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删除一个索引。
语法：
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sql-command ::=
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DROP INDEX [database-name .] index-name
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例子：
DROP INDEX idx_email;
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数据操作
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INSERT
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将新行插入到表。
语法：
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sql-statement ::=
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INSERT [OR conflict-algorithm] INTO [database-name .] table-name [(column-list)] VALUES(value-list) |
INSERT [OR conflict-algorithm] INTO [database-name .] table-name [(column-list)] select-statement
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UPDATE
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更新表中的现有数据。
语法：
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sql-statement ::=
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UPDATE [ OR conflict-algorithm ] [database-name .] table-name
SET assignment [, assignment]*
[WHERE expr]
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assignment ::=
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column-name = expr
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DELETE
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从表中删除行。
语法：
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sql-statement ::=
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DELETE FROM [database-name .] table-name [WHERE expr]
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SELECT
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从表中检索数据。
语法：
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sql-statement ::=
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SELECT [ALL | DISTINCT] result [FROM
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