Summary: in this tutorial, you will learn how to insert data into a table in the PostgreSQL database using JDBC. Inserting one row into a table We’ll use the products table from the sales database for the demonstration. Defining a Product class The following creates Product.java file and...
c:\>psql exampledb < user.sql // 将user.sql文件导入到exampled数据库中 postgres=# \h select // 精细显示SQL命令中的select命令的使用方法 postgres=# \l // 显示所有数据库 postgres=# \dt // 显示当前数据库中的所有表 postgres=# \d [table_name] // 显示当前数据库的指定表的表结构 postgres...
例如:当表中不存在某记录时,才插入这条记录。 INSERTINTO表名(列名1, 列名2)SELECT'值1','值2'WHERENOTEXISTS(SELECT*FROM表名WHERE列名1='值1', 列名2='值2'); 参考 PostgreSQL: Documentation: 10: INSERT This example inserts some rows into table films from a table tmp_films with the same col...
INSERT INTO TABLE_NAME (column1, column2, column3,...columnN)VALUES (value1, value2, value3,...valueN); 例:insert into postgtest (title,content) values('title1','content1'); 执行结果INSERT 0 1 ( INSERT 0 # 插入多行返回的信息, # 为插入的行数。)检索 ...
You are now connected to database"test"asuser"postgres".test=# create tabletb_mytps(i int,namevarchar(32))tablespace mytbs;CREATETABLE 插入实验数据 代码语言:javascript 复制 insert intotb_mytps(i,name)values(2,'name2');insert intotb_mytps(i,name)values(3,'name3');insert intotb_mytps...
CREATE TABLE user_tbl(name VARCHAR(20), signup_date DATE); # 插入数据 INSERT INTO user_tbl(name, signup_date) VALUES('张三', '2013-12-22'); # 选择记录 SELECT * FROM user_tbl; # 更新数据 UPDATE user_tbl set name = '李四' WHERE name = '张三'; ...
Example 1: Adding a New Column In the followingALTER TABLEstatement, theADD COLUMNclause will be used to insert a new column in the “emp_data” table: ALTER TABLE emp_data ADD COLUMN emp_age SMALLINT; To verify the table alteration, use the “\d” command followed by the table name,...
postgres=# drop table t_ret; DROP TABLE postgres=# create table t_ret(id int, info text, crt_time timestamp); CREATE TABLE postgres=# insert into t_ret values (1,’digoal’,now()), (2,’DIGOAL’,now()), (3,’digoal’,now()), (4,’abc’,now()); INSERT 0 4 postgres=# ...
在下面的例子中,副本example01-1有最高的优先级。 <postgresql><port>5432</port><user>clickhouse</user><password>qwerty</password><replica><host>example01-1</host><priority>1</priority></replica><replica><host>example01-2</host><priority>2</priority></replica><db>db_name</db><table>table...
BEGIN;BEGIN;-- 子事务INSERTINTOnon_existent_tableVALUES(1);EXCEPTIONWHENundefined_tableTHENRAISE WARNING'Table does not exist';ROLLBACK;-- 回滚子事务END;COMMIT;-- 主事务继续 1. 2. 3. 4. 5. 6. 7. 8. 9. 3. 性能开销 每个保存点会增加额外的事务管理开销,频繁创建保存点可能影响性能。建议:...