H2数据库使用
所属分类 H2
浏览量 1377
Connection Modes
Embedded mode (local connections using JDBC)
Server mode (remote connections using JDBC or ODBC over TCP/IP)
Mixed mode (local and remote connections at the same time)
内存模式
jdbc:h2:mem:testdb
不指定DBName,以私有方式启动,只允许一个连接
嵌入式
jdbc:h2:file:~/h2/DBName
第一次连接自动创建数据库
服务模式
web server 支持使用浏览器访问H2 Console
TCP server 支持客户端/服务器端的连接方式
PG server 支持PostgreSQL客户端
使用用户主目录
jdbc:h2:tcp://localhost/~/test
使用绝对路径
jdbc:h2:tcp://localhost//data/test
连接参数 参考 pdf Database URL Overview
连接字符串参数
DB_CLOSE_DELAY
MODE=MySQL 兼容模式,兼容多种数据库,DB2、Derby、HSQLDB、MSSQLServer、MySQL、Oracle、PostgreSQL
AUTO_RECONNECT=TRUE 连接丢失后自动重新连接
AUTO_SERVER=TRUE 允许开启多个连接
TRACE_LEVEL_SYSTEM_OUT TRACE_LEVEL_FILE
输出跟踪日志到控制台或文件, 取值0为OFF,1为ERROR(默认值),2为INFO,3为DEBUG
SET TRACE_MAX_FILE_SIZE 跟踪日志文件的大小,默认16M
Opening a Database Only if it Already Exists
The connection only succeeds when the database already exists.
jdbc:h2:/data/sample;IFEXISTS=TRUE
Automatic Mixed Mode
Multiple processes can access the same database without having to start the server manually.
This feature doesn't work with in-memory databases.
jdbc:h2:/data/test;AUTO_SERVER=TRUE
非混合模式只允许一个进程打开数据库
Exception in thread "main" org.h2.jdbc.JdbcSQLNonTransientConnectionException: Database may be already in use: null.
Possible solutions: close all other connection(s); use the server mode [90020-200]
Caused by: java.lang.IllegalStateException: The file is locked: nio:/Users/dugang/h2/test.mv.db [1.4.200/7]
Page Size
The page size for new databases is 2 KB (2048),
unless the page size is set explicitly in the database URL using PAGE_SIZE= when the database is created.
The page size of existing databases can not be changed, so this property needs to be set when the database is created.
Page Size 默认 2 KB ,不可修改
Using the Trace Options
The servers can be started in different ways, one is using the Server tool.
Starting the server doesn't open a database - databases are opened as soon as a client connects.
连接时打开数据库
java -cp h2*.jar org.h2.tools.Server
-web 启动支持H2 Console的服务
-webPort $port 服务启动端口,默认8082
-browser 启动H2 Console web管理页面
-tcp 使用TCP server模式启动
-pg 使用PG server模式启动
-tcpAllowOthers -pgAllowOthers -webAllowOthers
java -cp h2*.jar org.h2.tools.Server -tcp -tcpPort 9300
java -cp h2-1.4.200.jar org.h2.tools.Server -tcp -tcpPort 9300
TCP server running at tcp://10.57.240.26:9300 (only local connections)
java -cp h2-1.4.200.jar org.h2.tools.Server -tcp -tcpAllowOthers -tcpPort 9300
TCP server running at tcp://10.57.240.26:9300 (others can connect)
-tcpAllowOthers 允许从其他机器连接
jdbc:h2:~/h2/test
jdbc:h2:~/h2/test;AUTO_SERVER=TRUE
jdbc:h2:tcp://localhost:9300/~/h2/test;AUTO_SERVER=TRUE
Starting the TCP Server within an Application
import org.h2.tools.Server;
...
// start the TCP Server
Server server = Server.createTcpServer(args).start();
...
// stop the TCP Server
server.stop();
基于web H2 client
https://gitee.com/dyyx/demos/tree/master/h2demo
上一篇
下一篇
H2 limits
列式存储引擎Parquet和ORC比较
parquet基本原理
ORC文件格式
flink基础
装逼词汇大全