Mysql、Oracle、Sqlserver三种数据源下查询元数据的方法

最近在做数据相关的平台，并且需要支持多数据源，所以把用到的sql记录一下

一.链接数据源

三种数据源的链接方式都是不同的，所以抽象了几个方法用于获取DB链接

• 数据源链接参数封装类

/**
 * @program: common-info
 * @description: 数据源属性封装类
 * @author: lvqiushi
 * @create: 2019-03-28 13:51
 **/
@Data
public class DataSourceAttrDTO implements Serializable {
    /**
     * 数据库类型，1mysql，2oracle
     */
    private Integer sourceType;

    /**
     * 数据库地址
     */
    private String sourceAddress;

    /**
     * 数据库端口号
     */
    private String sourcePort;

    /**
     * 用户名
     */
    private String userName;

    /**
     * 密码
     */
    private String userPassword;

    /**
     * 数据库名称
     */
    private String dbName;
}

• 不同数据源驱动类、前缀的枚举类

/**
 * @program: common-info
 * @description: 数据库类型枚举类
 * @author: lvqiushi
 * @create: 2019-04-01 19:13
 **/
@Getter
@AllArgsConstructor
public enum DataBaseTypeEnum {
    MYSQL(1, "mysql类型数据库", "com.mysql.jdbc.Driver", "jdbc:mysql://"),
    ORACLE(2, "oracle类型数据库", "oracle.jdbc.driver.OracleDriver", "jdbc:oracle:thin:@"),
    SQL_SERVER(3, "sql server", "com.microsoft.sqlserver.jdbc.SQLServerDriver", "jdbc:sqlserver://");

    /**
     * 类型
     */
    private Integer type;

    /**
     * 描述
     */
    private String desc;

    /**
     * 数据库驱动器名称
     */
    private String driver;

    /**
     * 数据库url前缀
     */
    private String urlPrefix;
}

• 获取数据库url方法，其中oracle使用了SID进行链接，所以一定要有示例名称

/**
	 * @Description: 根据链接参数拼接
	 * @param dataSourceAttrDTO	数据源参数
	 * @return: java.lang.String
	 * @Author: lvqiushi
	 * @Date: 2019-04-01
	 */
	private String getDBUrl(DataSourceAttrDTO dataSourceAttrDTO) {
        if (dataSourceAttrDTO.getJdbcUrl() != null) {
            return dataSourceAttrDTO.getJdbcUrl();
        }
        // dbName有可能为null 要注意判断
		String dbName = "";
		if (StringUtils.isNotEmpty(dataSourceAttrDTO.getDbName())) {
			if (DataBaseTypeEnum.SQL_SERVER.getType().equals(dataSourceAttrDTO.getSourceType())) {
				dbName = ";databaseName=" + dataSourceAttrDTO.getDbName();
			} else {
				dbName = "/" + dataSourceAttrDTO.getDbName();
			}
		}

		if (DataBaseTypeEnum.MYSQL.getType().equals(dataSourceAttrDTO.getSourceType())) {
			return DataBaseTypeEnum.MYSQL.getUrlPrefix() +
					dataSourceAttrDTO.getSourceAddress() + ":" +
					dataSourceAttrDTO.getSourcePort() + dbName;
		} else if (DataBaseTypeEnum.ORACLE.getType().equals(dataSourceAttrDTO.getSourceType())) {
            return DataBaseTypeEnum.ORACLE.getUrlPrefix() +
                    dataSourceAttrDTO.getSourceAddress() + ":" +
                    dataSourceAttrDTO.getSourcePort() + dbName;
		} else if (DataBaseTypeEnum.SQL_SERVER.getType().equals(dataSourceAttrDTO.getSourceType())) {
            return DataBaseTypeEnum.SQL_SERVER.getUrlPrefix() +
                    dataSourceAttrDTO.getSourceAddress() + ":" +
                    dataSourceAttrDTO.getSourcePort() + dbName;
		}
		return null;
	}

• 获取driverManager的方法

	/**
	 * @Description: 获取数据库驱动管理器
	 * @param dataSource
	 * @return: org.springframework.jdbc.datasource.DriverManagerDataSource
	 * @Author: lvqiushi
	 * @Date: 2019-04-02
	 */
	private DriverManagerDataSource getDriverManager(DataSourceAttrDTO dataSource) {
		DriverManagerDataSource dataSourceManager = new DriverManagerDataSource();
		dataSourceManager.setDriverClassName(this.getDBDriverName(dataSource.getSourceType()));
		dataSourceManager.setUrl(this.getDBUrl(dataSource));
		dataSourceManager.setUsername(dataSource.getUserName());
		dataSourceManager.setPassword(dataSource.getUserPassword());

		return dataSourceManager;
	}

二.Mysql查询元数据sql

• 查询所有数据库列表

show databases

• 查询数据库中所有表列表

select table_name tableName, table_comment tableComment from information_schema.tables where table_schema = (select database())

• 查询表中元数据信息
  返回结果列为 字段名称-字段类型-完整字段类型-字段注释-字段索引键-额外信息

select column_name columnName, data_type dataType, column_type, column_comment columnComment,column_default, is_nullable, column_key columnKey, extra 
from information_schema.columns 
where table_name = ? and table_schema = (select database()) 
order by ordinal_position

三.Oracle查询元数据sql

• 查询数据库中所有表列表

select table_name, comments from all_tab_comments
where TABLE_TYPE = 'TABLE'
and owner not in ('SYS','SYSTEM', 'MDSYS', 'APEX_030200','XDB','OLAPSYS','EXFSYS','CTXSYS')

• 查询表的元数据信息
  返回结果列为 表名-字段名称-字段类型-字段长度-字段备注-是否为空-是否主键

select t1.table_name,t1.column_name,data_type,data_length,comments,
   case 
   		when nullable = 'Y' then 1
   		when nullable = 'N' then 0
   		else 0 
   end as nullable,
   case 
   		when t3.column_name is null then 0
   		else 1 
   end as is_primary ,data_scale 
   from user_col_comments t2 
   left join user_tab_cols t1 on t1.column_name = t2.column_name and t1.table_name = t2.table_name
   left join (
   		select col.column_name as column_name,con.table_name as table_name from user_constraints con,user_cons_columns col
   		where con.constraint_name = col.constraint_name 
   		and con.constraint_type = 'P'
   ) t3 on t3.table_name = t1.table_name and t1.column_name = t3.column_name
 where t1.table_name = ?

四.Sqlserver查询元数据sql

• 查询所有数据库列表

select Name FROM Master.dbo.SysDatabases ORDER BY Name

• 查询数据库中所有表列表

select tbs.name , CAST(ds.value AS NVARCHAR(128)) AS comment  
FROM sysObjects tbs
left join sys.extended_properties ds on ds.major_id=tbs.id and ds.minor_id=0
Where XType='U'

• 查询表中元数据信息
  返回结果列为 返回结果列为 表名-字段名称-字段类型-字段长度-字段备注-是否为空-是否主键

select
	obj.name as tableName,
	col.name as columnName,
	t.name as dataType,
	col.max_length as dataLength,
	CAST(ep.value  AS NVARCHAR(128)) AS comment,
	col.is_nullable as isNullable,
	(
	select top 1 ind.is_primary_key from sys.index_columns ic
	left join sys.indexes ind
	on ic.object_id=ind.object_id
	and ic.index_id=ind.index_id
	and ind.name like 'PK_%'
	where ic.object_id=obj.object_id
	and ic.column_id=col.column_id
	) as isPrimaryKey
from sys.objects obj 
	inner join sys.columns col on obj.object_id=col.object_id
	left join sys.types t on t.user_type_id=col.user_type_id
	left join sys.extended_properties ep on ep.major_id=obj.object_id
	and ep.minor_id=col.column_id
	and ep.name='MS_Description'
where obj.name = ?