二. 索引的存储情况检查 Oracle为数据库中的所有数据分配逻辑结构空间。数据库空间的单位是数据块(block)、范围(extent)和段(segment)。 Oracle数据块(block)是Oracle使用和分配的最小存储单位。它是由数据库建立时设置的DB_BLOCK_SIZE决定的。一旦数据库生成了,数据块的大小不能改变。要想改变只能重新建立数据库。...
</insert> 对于Oracle不支持主键自增,需要序列替换,所以在SQL写法上略有不同,需要在insert语句前加个 <selectKey>...</selectKey>告知Mybatis主键如何生成(selectKey中间的内容有省略,实际是生成主键的SQL)。 (2)批量更新 <update id="batchUpdate" parameterType="java.util.List"> <foreach close="" collection...
Specifying DEFAULT for the update value sets the value of the column to the default defined for that table. The DEFAULT literal is the only value which you can directly assign to a generated column. Whenever you alter the value of a column referenced by thegeneration-clauseof a generated colu...
I thought if I updated one column it would only bring the change for one column. Anyone can point to a location in the documentaion where this is described? Is it the replicate that see the update on the table and wants to see values for all columns in the table or is it extract th...
Specify a different name (alias) for the column expression. Oracle will use this alias in the column heading. The AS keyword is optional. The alias effectively renames the select list item for the duration of the query. The alias can be used in the order_by_clause, but not other clause...
异常如下: org.mybatis.spring.MyBatisSystemException: nested exception is org.apache.ibatis.type.TypeException: Could not set parameters for mapping: ParameterMapping{property='et.xmmxywsx', mode=IN, javaType=class java.lang.Object, jdbcType=null, numericScale=null, resultMapId='null', jdbcTypeName...
Security vulnerabilities addressed by this Critical Patch Update affect the products listed below. The product area is shown in the Patch Availability Document column.Please click on the links in the Patch Availability Document column below to access the documentation for patch availability information ...
Also, Tables with Composite Keys have no Identity column, so no functionality for them in that case either.var bulkConfig = new BulkConfig { SetOutputIdentity = true, BatchSize = 4000 }; context.BulkInsert(entities, bulkConfig); context.BulkInsertOrUpdate(entities, new BulkConfig { SetOutput...
The alias is used as the expression’s column name and can be used with ORDER BY or HAVING clauses. For example: mysql> SELECT CONCAT(last_name,', ',first_name) AS full_name FROM mytable ORDER BY full_name; You cannot use a column alias in a WHERE clause because the column value...
columnName String 字段名 columnCnName String 字段中文名 businessDefine String 业务 primaryKey Boolean 是否主键 securityLevel String 安全等级 dataClassification String 数据类别 columnType String 字段类型 columnSize String 字段size columnPrecision String 字段precision columnFormat String 字段格式 unit String 度...