Solutions:
1. Use CMD to enter the command line
2. Sqlplus/nolog

3、conn/as sysdba

4、startup

Then use sqlplus to enter the command

Reproduced in: https://www.cnblogs.com/bingyunbuxi/p/9917900.html

reference resources: http://database.guide/what-is-a-database-schema/

In database, schema (pronounced “skee MUH” or “skee MAH”, called schema in Chinese) is the organization and structure of database. Both schema and schemata can be used as plural forms. Schema objects include table, column, data type, view, stored procedures, relationships, primary key, foreign key, etc. Database schema can be represented by a visual graph, which shows database objects and their relationships

The above is a simple example of a schema diagram, showing three tables and their data types, the relationship between tables, and primary and foreign keys. The following is a more complex example of a database schema.

In this case, the pattern diagram is divided into four parts

(1) Customer data: data related to customers, such as name, address, etc

(2) Business: data needed by the business, such as employees, store location, payment details, etc

(3) Inventory: details of all products. Here, the product is a movie, so it contains movie title, category, actor and other data.

(4) Views: special views on the data used for evaluation, so we can further create a database through these schema diagrams. In fact, MySQL workbench allows us to generate a create database directly from the diagram Table script, and then we can directly use this script to create a database, and also directly convert a database into a relational chart.

Are schema and database the same?

When it comes to database schema, there are many doubts. The problem often arises whether there is a difference between schema and database, and if so, where is the difference.

It depends on the database vendor

Part of the confusion about schema is that database systems tend to handle schema in their own way

(1) MySQL documents point out that in physics, schema and database are synonymous, so schema and database are the same thing.

(2) However, Oracle documents point out that some objects can be stored in the database, but not in the schema. Therefore, schema and database are not the same thing.

(3) According to this SQL Server technical article, schema is an independent entity within SQL server. So, they are not the same thing.

Therefore, depending on the RDBMS you are using, the schema and database may not be the same.

How to define schema in SQL standard?

In ISO / IEC 9075-1 SQL standard, schema is defined as a persistent, named collection of descriptors. If you are confused about the definition of schema before, I hope it will be better, at least not worse after reading my article.

In a broad sense

Another reason for the confusion may be that the term schema has such a wide range of meanings, because it has different meanings in different environments. The word schema comes from the Greek SKH ē Ma, which means form, figure, shape or plan. In psychology, schema is used to describe the organized thinking or behavior patterns of organizational information categories and their relationships. Before we design a database, we also need to look at the types of information in the data and the relationship between them. Before we start to use the physical schema in DBMS, we need to create a conceptual schema. When discussing patterns in software development, we can discuss conceptual patterns, physical patterns, internal patterns, external patterns, logical patterns, etc., each of which has its own specific meaning.

Schema definition of DBMS

Here are the schema definitions of three leading relational database systems:

MySQL

Conceptually, a schema is a set of interrelated database objects, such as tables, table columns, data types of the columns, indexes, foreign keys, and so on. These objects are connected through SQL syntax, because the columns make up the tables, the foreign keys refer to tables and columns, and so on. Ideally, they are also connected logically, working together as part of a unified application or flexible framework. For example, theINFORMATION_ SCHEMA and performance_ schema databases use “schema” in their names to emphasize the close relationships between the tables and columns they contain.

In MySQL, physically, aschema is synonymous with adatabase. You can substitute the keywordSCHEMA instead ofDATABASE in MySQL SQL syntax, for example using CREATE SCHEMA instead of CREATE DATABASE.

Some other database products draw a distinction. For example, in the Oracle Database product, aschema represents only a part of a database: the tables and other objects owned by a single user.

MySQL official documents point out that conceptually, a schema is a set of interrelated database objects, such as tables, table columns, column data types, indexes, foreign keys, and so on. But from the physical level, schema and database are synonymous. You can use the keyword schema instead of database in the SQL syntax of MySQL, for example, create schema instead of create database .

Reference: MySQL glossary, MySQL 5.7 reference manual. Mysql, retrieved 6 June 2016.

SQL Server

The names of tables, fields, data types, and primary and foreign keys of a database.

SQL Server official documents point out that the schema contains the database table, field, data type and the name of primary key and foreign key. Reference: SQL Server glossary. SQL Server 2016 technical documentation. Microsoft developer network. Retrieved 6 June 2016

Oracle Database

The schema system in Oracle is very different from other database systems. The schema of Oracle is closely related to database users.

A schema is a collection of logical structures of data, or schema objects. A schema is owned by a database user and has the same name as that user. Each user owns a single schema.

Oracle official documents point out that schema is a collection of logical structures of data or schema objects, which is owned by database users and has the same name as the user, that is to say, each user has an independent schema.

Reference: Oracle database objects. Oracle database online documentation 12C release 1 (12.1). Oracle help center. Retrieved 6 June 2016

If you want to know more about schema, you can refer to this article schema definitions by DBMS

Create schema

Although the above three DBMS are different in defining schema, they all support create schema statements.

MySQL

In mysql, create schema creates a database because create schema is synonymous with create database . In other words, you can use create schema or create database to create a database.

Oracle Database

In Oracle, create schema statement does not actually create a schema, because a schema has been created for database users when creating users, that is to say, create user creates a schema in Oracle, create user creates a schema Schema statements allow you to associate schema with tables and views, and authorize them, so that you don’t have to issue multiple SQL statements in multiple transactions.

SQL Server

In SQL server, create schema creates a schema by name. Unlike mysql, the create schema statement creates a schema that is defined separately to the database. Different from Oracle, the create schema statement actually creates a schema (as mentioned earlier, this statement does not create a schema in Oracle). In SQL server, once the schema is created, users and objects can be added to the schema.

summary

The word schema can be used in many different environments. When creating a schema in a specific DBMS, you need to use the DBMS specific definition mode. When you switch to a new DBMS, you must check how the system defines the schema.

2016-03-28 17:23:38.420 main DEBUG [org.springframework.beans.factory.support.DefaultListableBeanFactory:463] - Finished creating instance of bean 'Sybase'
2016-03-28 17:23:38.420 main  INFO [org.springframework.jdbc.support.SQLErrorCodesFactory:126] - SQLErrorCodes loaded: [DB2, Derby, H2, HSQL, Informix, MS-SQL, MySQL, Oracle, PostgreSQL, Sybase]
2016-03-28 17:23:38.420 main DEBUG [org.springframework.jdbc.support.SQLErrorCodesFactory:199] - Looking up default SQLErrorCodes for DataSource [com.jd.im.data.dataresource.JdDataSourceDbcp@14021a9]
2016-03-28 17:23:38.423 main DEBUG [org.springframework.jdbc.support.SQLErrorCodesFactory:217] - Database product name cached for DataSource [com.jd.im.data.dataresource.JdDataSourceDbcp@14021a9]: name is 'MySQL'
2016-03-28 17:23:38.423 main DEBUG [org.springframework.jdbc.support.SQLErrorCodesFactory:175] - SQL error codes for 'MySQL' found
2016-03-28 17:23:38.423 main DEBUG [org.springframework.jdbc.support.SQLErrorCodeSQLExceptionTranslator:399] - Translating SQLException with SQL state '42000', error code '1064', message [  
--- The error occurred while applying a parameter map.  
--- Check the mall.org.updateById-InlineParameterMap.  
--- Check the statement (update failed).  
--- Cause: com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'WHERE id = 12' at line 1]; SQL was [] for task [SqlMapClient operation]
2016-03-28 17:23:38.424 main ERROR [com.jd.dd.mall.service.waiter.impl.OrgService‫Impl:97] - IM data access exception
com.jd.im.data.exception.IMDataAccessException: IM data access exception
	at com.jd.im.data.dataresource.IMSqlMapClientTemplateForMultDs.handleUserException(IMSqlMapClientTemplateForMultDs.java:280)
	at com.jd.im.data.dataresource.IMSqlMapClientTemplateForMultDs.update(IMSqlMapClientTemplateForMultDs.java:160)
	at com.jd.dd.mall.service.waiter.impl.OrgService‫Impl.updateById(OrgService‫Impl.java:106)
	at com.jd.dd.mall.service.waiter.impl.OrgService‫Impl.add(OrgService‫Impl.java:92)
	at com.jd.dd.mall.web.controller.waiter.OrgManageController.addOrg(OrgManageController.java:85)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
	at java.lang.reflect.Method.invoke(Method.java:597)
	at org.springframework.web.method.support.InvocableHandlerMethod.invoke(InvocableHandlerMethod.java:219)
	at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:132)
	at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:104)
	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:746)
	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:687)
	at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:80)
	at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:925)
	at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:856)
	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:915)
	at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:822)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
	at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:796)
	at org.springframework.test.web.servlet.TestDispatcherServlet.service(TestDispatcherServlet.java:66)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)
	at org.springframework.mock.web.MockFilterChain$ServletFilterProxy.doFilter(MockFilterChain.java:168)
	at org.springframework.mock.web.MockFilterChain.doFilter(MockFilterChain.java:136)
	at org.springframework.test.web.servlet.MockMvc.perform(MockMvc.java:134)
	at com.jd.service.waiter.OrgControllerTest.add(OrgControllerTest.java:53)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
	at java.lang.reflect.Method.invoke(Method.java:597)
	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44)
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41)
	at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20)
	at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28)
	at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:74)
	at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:83)
	at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:72)
	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:231)
	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:88)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:193)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:52)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:191)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:42)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:184)
	at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
	at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:71)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:236)
	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:174)
	at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)
	at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:459)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:675)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192)
Caused by: org.springframework.jdbc.BadSqlGrammarException: SqlMapClient operation; bad SQL grammar []; nested exception is com.ibatis.common.jdbc.exception.NestedSQLException:   
--- The error occurred while applying a parameter map.  
--- Check the mall.org.updateById-InlineParameterMap.  
--- Check the statement (update failed).  
--- Cause: com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'WHERE id = 12' at line 1
	at org.springframework.jdbc.support.SQLErrorCodeSQLExceptionTranslator.doTranslate(SQLErrorCodeSQLExceptionTranslator.java:233)
	at org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:72)
	at org.springframework.orm.ibatis.SqlMapClientTemplate.execute(SqlMapClientTemplate.java:206)
	at org.springframework.orm.ibatis.SqlMapClientTemplate.update(SqlMapClientTemplate.java:381)
	at com.jd.im.data.dataresource.IMSqlMapClientTemplateForMultDs.update(IMSqlMapClientTemplateForMultDs.java:134)
	... 54 more
Caused by: com.ibatis.common.jdbc.exception.NestedSQLException:   
--- The error occurred while applying a parameter map.  
--- Check the mall.org.updateById-InlineParameterMap.  
--- Check the statement (update failed).  
--- Cause: com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'WHERE id = 12' at line 1
	at com.ibatis.sqlmap.engine.mapping.statement.MappedStatement.executeUpdate(MappedStatement.java:107)
	at com.ibatis.sqlmap.engine.impl.SqlMapExecutorDelegate.update(SqlMapExecutorDelegate.java:457)
	at com.ibatis.sqlmap.engine.impl.SqlMapSessionImpl.update(SqlMapSessionImpl.java:90)
	at org.springframework.orm.ibatis.SqlMapClientTemplate$9.doInSqlMapClient(SqlMapClientTemplate.java:383)
	at org.springframework.orm.ibatis.SqlMapClientTemplate$9.doInSqlMapClient(SqlMapClientTemplate.java:381)
	at org.springframework.orm.ibatis.SqlMapClientTemplate.execute(SqlMapClientTemplate.java:203)
	... 56 more

and my Ibatis SQL

<update id="updateById"  parameterClass="Org">
		UPDATE org
		SET	name = #name:VARCHAR#,
			<isNotNull property="tree_level">tree_level = #tree_level#, </isNotNull>
			<isNotNull property="yn">yn = #yn#, </isNotNull>
			<isNotNull property="route">route = #route:VARCHAR#, </isNotNull>
			`version` = `version` + 1,
			<isNotNull property="editor">editor = #editor:VARCHAR#  </isNotNull>
			
		WHERE id = #id#
	</update>

like this stack does not clearly indicate the cause of SQL problems, troubleshooting problems must be according to the error code to check. Baidu checked the 1064 error code. The column name of the table overlaps with the Mysql keyword. OK, I took this SQL close to the mysql client query interface and found that the name field changed to the color of the keyword. I thought I found the problem, so I put back quotes around the name. Run the unit test again and report an error of 1064.

There is no way out, only ibATIS executed SQL typing out, put into mysql client to see. OK, log4J plus log, the execution of IBATIS SQL typing out. Run the unit test again and the SQL doesn’t come out.
There is a feeling of frustration that should not be called indolent every day!
You have no choice but to look at SQL with your eyes. If the Editor field is null, then there are extra commas before the WHERE. Adjust the SQL.

	<update id="updateById"  parameterClass="Org">
		UPDATE org
		SET id = #id# ,
			<isNotNull property="name">`name` = #name:VARCHAR#, </isNotNull>
			<isNotNull property="tree_level">tree_level = #tree_level#, </isNotNull>
			<isNotNull property="yn">yn = #yn#, </isNotNull>
			<isNotNull property="route">route = #route:VARCHAR#, </isNotNull>
			<isNotNull property="editor">editor = #editor:VARCHAR# , </isNotNull>
			`version` = `version` + 1
		WHERE id = #id#
	</update>

Then run the unit test and the SQL executes successfully. Just log can not type out SQL, this time to type out. Where have you been when I need you?Mysql’s error code is not reliable at all! The SQL syntax is obviously wrong, but the code of 1064 is quoted.

Remove the back quotes from the Name and Version fields and the SQL will still execute normally. Fun!

Restart the listening service after the modification to see if the problem has been resolved. Again, I encountered an error where I was unable to get more information from the socket. Ora file, as shown in the figure above. Simply comment out the #(PROGRAM = extproc) line and the problem is solved. Now restart the service again and find that you can finally connect, and you’re done.