一.结构定义
1.CREATE TABLE:创建新表。
sql-command ::= CREATE [TEMP | TEMPORARY] TABLE table-name (
column-def [, column-def]*
[, constraint]*
)
sql-command ::= CREATE [TEMP | TEMPORARY] TABLE [database-name.] table-name AS select-statement
column-def ::= name [type] [[CONSTRAINT name] column-constraint]*
type ::= typename |
typename ( number ) |
typename ( number , number )
column-constraint ::= NOT NULL [ conflict-clause ] |
PRIMARY KEY [sort-order] [ conflict-clause ] |
UNIQUE [ conflict-clause ] |
CHECK ( expr ) [ conflict-clause ] |
DEFAULT value |
COLLATE collation-name
constraint ::= PRIMARY KEY ( column-list ) [ conflict-clause ] |
UNIQUE ( column-list ) [ conflict-clause ] |
CHECK ( expr ) [ conflict-clause ]
conflict-clause ::= ON CONFLICT conflict-algorithm
2.CREATE VIEW: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。
sql-command ::= CREATE [TEMP | TEMPORARY] VIEW [database-name.] view-name AS select-statement
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。
3.CREATE TRIGGER: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。
sql-statement ::= CREATE [TEMP | TEMPORARY] TRIGGER trigger-name [ BEFORE | AFTER ]
database-event ON [database-name .] table-name
trigger-action
sql-statement ::= CREATE [TEMP | TEMPORARY] TRIGGER trigger-name INSTEAD OF
database-event ON [database-name .] view-name
trigger-action
database-event ::= DELETE |
INSERT |
UPDATE |
UPDATE OF column-list
trigger-action ::= [ FOR EACH ROW | FOR EACH STATEMENT ] [ WHEN expression ]
BEGIN
trigger-step ; [ trigger-step ; ]*
END
trigger-step ::= update-statement | insert-statement |
delete-statement | select-statement
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';
4.CREATE INDEX:为给定表或视图创建索引。
sql-statement ::= CREATE [UNIQUE] INDEX index-name
ON [database-name .] table-name ( column-name [, column-name]* )
[ ON CONFLICT conflict-algorithm ]
column-name ::= name [ COLLATE collation-name] [ ASC | DESC ]
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。
二.结构删除
1.DROP TABLE:删除表定义及该表的所有索引。
sql-command ::= DROP TABLE [database-name.] table-name
例子:
DROP TABLE customers;
2.DROP VIEW:删除一个视图。
sql-command ::= DROP VIEW view-name
例子:
DROP VIEW master_view;
3.DROP TRIGGER:删除一个触发器。
sql-statement ::= DROP TRIGGER [database-name .] trigger-name
例子:
DROP TRIGGER update_customer_address;
4.DROP INDEX:删除一个索引
sql-command ::= DROP INDEX [database-name .] index-name
例子:
DROP INDEX idx_email;
三,数据操作
1.INSERT:将新行插入到表。
sql-statement ::= 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
2.UPDATE:更新表中的现有数据。
sql-statement ::= UPDATE [ OR conflict-algorithm ] [database-name .] table-name
SET assignment [, assignment]*
[WHERE expr]
assignment ::= column-name = expr
3.DELETE:从表中删除行。
sql-statement ::= DELETE FROM [database-name .] table-name [WHERE expr]
4.SELECT:从表中检索数据。
sql-statement ::= SELECT [ALL | DISTINCT] result [FROM table-list]
[WHERE expr]
[GROUP BY expr-list]
[HAVING expr]
[compound-op select]*
[ORDER BY sort-expr-list]
[LIMIT integer [( OFFSET | , ) integer]]
result ::= result-column [, result-column]*
result-column ::= * | table-name . * | expr [ [AS] string ]
table-list ::= table [join-op table join-args]*
table ::= table-name [AS alias] |
( select ) [AS alias]
join-op ::= , | [NATURAL] [LEFT | RIGHT | FULL] [OUTER | INNER | CROSS] JOIN
join-args ::= [ON expr] [USING ( id-list )]
sort-expr-list ::= expr [sort-order] [, expr [sort-order]]*
sort-order ::= [ COLLATE collation-name ] [ ASC | DESC ]
compound_op ::= UNION | UNION ALL | INTERSECT | EXCEPT
5.REPLACE:类似INSERT。
sql-statement ::= REPLACE INTO [database-name .] table-name [( column-list )] VALUES ( value-list ) |
REPLACE INTO [database-name .] table-name [( column-list )] select-statement
四。事务处理
1.BEGIN TRANSACTION:标记一个事务的起始点。
sql-statement ::= BEGIN [TRANSACTION [name]]
2.END TRANSACTION:标记一个事务的终止。
sql-statement ::= END [TRANSACTION [name]]
3.COMMIT TRANSACTION:标志一个事务的结束。
sql-statement ::= COMMIT [TRANSACTION [name]]
4.ROLLBACK TRANSACTION:将事务回滚到事务的起点.
sql-statement ::= ROLLBACK [TRANSACTION [name]]
五。其他操作
1.COPY:主要用于导入大量的数据。
sql-statement ::= COPY [ OR conflict-algorithm ] [database-name .] table-name FROM filename
[ USING DELIMITERS delim ]
例子:
COPY customers FROM customers.csv;
2.ATTACH DATABASE:附加一个数据库到当前的数据库连接。
sql-statement ::= ATTACH [DATABASE] database-filename AS database-name
3.DETTACH DATABASE:从当前的数据库分离一个使用ATTACH DATABASE附加的数据库。
sql-command ::= DETACH [DATABASE] database-name
六。SQLite内建函数表:
算术函数 | |
abs(X) | 返回给定数字表达式的绝对值。 |
max(X,Y[,...]) | 返回表达式的最大值。 |
min(X,Y[,...]) | 返回表达式的最小值。 |
random(*) | 返回随机数。 |
round(X[,Y]) | 返回数字表达式并四舍五入为指定的长度或精度。 |
字符处理函数 | |
length(X) | 返回给定字符串表达式的字符个数。 |
lower(X) | 将大写字符数据转换为小写字符数据后返回字符表达式。 |
upper(X) | 返回将小写字符数据转换为大写的字符表达式。 |
substr(X,Y,Z) | 返回表达式的一部分。 |
randstr() | |
quote(A) | |
like(A,B) | 确定给定的字符串是否与指定的模式匹配。 |
glob(A,B) | |
条件判断函数 | |
coalesce(X,Y[,...]) | |
ifnull(X,Y) | |
nullif(X,Y) | |
集合函数 | |
avg(X) | 返回组中值的平均值。 |
count(X) | 返回组中项目的数量。 |
max(X) | 返回组中值的最大值。 |
min(X) | 返回组中值的最小值。 |
sum(X) | 返回表达式中所有值的和。 |
其他函数 | |
typeof(X) | 返回数据的类型。 |
last_insert_rowid() | 返回最后插入的数据的ID。 |
sqlite_version(*) | 返回SQLite的版本。 |
change_count() | 返回受上一语句影响的行数。 |
last_statement_change_count() |