ORACLE数据字典 表名:USER_TAB_COLUMNS TABLE_NAME 表、视图或聚簇名 COLUMN_NAME 列名 DATA_TYPE 列数据类型 DATA_TYPE_MOD DATA_TYPE_OWNER DATA_LENGTH 列最大长度 DATA_PRECISION Number数据类型的十进制精度,Float数据类型的二进制精度,对其他数据类型则为NULL DATA_SCALE 小数点右边位数 NULLABLE 列是否可为...
status - status of the constraint (ENABLED/DISABLED) Rows One row represents one check constraint and its column in a database Scope of rows: (A) all check constraints with columns on a table accessible to the current user in Oracle database, (B) all check constraints with columns on a ...
2、 FREELIST(自由列表) Oracle通过维护FREELIST列表来记录或更新所有可用的数据块。当执行INSERT语句时,Oracle首先在FREELIST列表上搜索可用的空闲数据块,搜索成功之后将数据插入到那个空闲块。块在FREELIST列表中的可用性由PCTFREE参数值来决定。起初一个空块在FREELIST列表上列出,并且会一直保留,直到空闲空间达到PCTFR...
select table_name,cache from user_tables where instr(cache,'Y')>0; 查看索引个数和类别 select index_name,index_type,table_name from user_indexes order by table_name; 查看索引被索引的字段 select * from user_ind_columns where index_name=upper('&index_name'); 查看索引的大小 select sum(byte...
oracle导出数据时出现Table xx contains one or more CLOB columns错误,这个是说表里面有多个clob类型,不能导出 PLSQL导出方式有三种,第一种导出.dmp文件,它是二进制文件,通用性比较好,可以跨平台使用。第二种导出.sql文件,它的好处在于可以看见sql语句,适合数据量小的情况,而且不能有大字段内容(blob、clob、long...
columns 和不指定任何参数的时候oracle会给所有字段做统计信息,在指定for indexed columns时,oracle只给[b]有索引的字段进行字段信息统计[/b],如果我们别有必要给所有字段统计信息时,这个属性就很有用了. --再综合前面的我们就会发现,如果在运行analyze table是我们不指定参数,oracle将收集对于特定表的所有统计信息(...
ORA-12983: cannot drop all columns in a table Change column properties If after adding a column you need to change its properties, use theMODIFYclause in theALTER TABLEstatement. As example, change the type ofcol1toNUMBER(10), and set its default value to2. ...
13、XTENTSNUMBERMinimum number of extents allowed in the segmentMAX_EXTENTSNUMBERMaximum number of extents allowed in the segmentPCT_INCREASENUMBERPercent by which to increase the size of the next extent to be allocatedFREELISTSNUMBERNumber of process freelists allocated to this segmentFREELIST_GROUPS...
Within the Oracle database that we have configured, there exists a FILLED_ORDERS table owned by the TTORAUSER user that holds a list of fulfilled trade orders. We will now create an AWT cache group for this table within ordermatching.
If you're using Power BI Report Server, consult the guidance in theOracle Connection Typearticle. Next steps Optimize Power Query when expanding table columns