关于数据库对象版本比较的脚本

原创于2006年12月28日，2009年10月15日迁移至此。

项目原因导致出现两个开发环境，主数据库环境因需求变更每天都需要进行脚本的修改，而报表服务器的脚本也需要同步更新，需求变更很少会同步提醒的；人工判断太过于麻烦，我又是一个懒人；只好写个脚本自动进行识别并加以运行了。

这只是一个简单的版本比较工具，事实上变更是很难判断的，例如表中新增了一个字段，导致顺序发生变更，这个时候你很难判断是新增还是修改的；诸如字段类型的修改.因此只能去判断表是否存在，字段是否存在，进而执行判断脚本，产生相应的表脚本和字段教本。

事实上Oracle有个DBMS_METADATA数据包提供了DLL脚本，不过包含了很多存储参数，对版本比较和对象生成没有什么意义。

--CREATE THE CREATE_TABLE SCRIPT, THOUGH WE CAN USE --LIKE select dbms_metadata.get_ddl('TABLE','TABLENAME','USERNAME') from dual; GET THE SQL SCRIPT --BUT IT IS NOT HELPFUL TO COMPARE THE DIFFERENT VERSION SELECT SQLTEXT FROM ( SELECT 'CREATE TABLE '||TABLE_NAME AS SQLTEXT,-1 AS COLUMN_ID,TABLE_NAME FROM USER_TABLES@REMOTEKGK UNION SELECT '(' AS SQLTEXT,0 AS COLUMN_ID,TABLE_NAME FROM USER_TABLES@REMOTEKGK UNION SELECT ');' AS SQLTEXT,100 AS COLUMN_ID,TABLE_NAME FROM USER_TABLES@REMOTEKGK UNION SELECT CASE WHEN DATA_TYPE='NUMBER' THEN CASE WHEN DATA_PRECISION IS NULL THEN COLUMN_NAME||' INTEGER,' ELSE COLUMN_NAME||' '||DATA_TYPE||'('||TO_CHAR(DATA_PRECISION)||','||TO_CHAR(DATA_SCALE)||')'||DECODE(COLUMN_ID,(SELECT MAX (B.COLUMN_ID) FROM USER_TAB_COLUMNS@REMOTEKGK B WHERE A.TABLE_NAME=B.TABLE_NAME),' ',',') END WHEN DATA_TYPE='NVARCHAR2' THEN COLUMN_NAME||' '||DATA_TYPE||'('||TO_CHAR(DATA_LENGTH/2)||')'||DECODE(COLUMN_ID,(SELECT MAX(B.COLUMN_ID) FROM USER_TAB_COLUMNS@REMOTEKGK B WHERE A.TABLE_NAME=B.TABLE_NAME),' ',',') WHEN DATA_TYPE IN ('CHAR','VARCHAR2') THEN COLUMN_NAME||' '||DATA_TYPE||'('||TO_CHAR(DATA_LENGTH)||')'||DECODE(COLUMN_ID,(SELECT MAX(B.COLUMN_ID) FROM USER_TAB_COLUMNS@REMOTEKGK B WHERE A.TABLE_NAME=B.TABLE_NAME),' ',',') WHEN DATA_TYPE IN ('DATE','BLOB','CLOB','LONG','NCLOB') THEN COLUMN_NAME||' '||DATA_TYPE||DECODE(COLUMN_ID,(SELECT MAX(B.COLUMN_ID) FROM USER_TAB_COLUMNS@REMOTEKGK B WHERE A.TABLE_NAME=B.TABLE_NAME),' ',',') END AS SQLTEXT, COLUMN_ID, A.TABLE_NAME FROM USER_TAB_COLUMNS@REMOTEKGK A Where A.table_name Like 'T%' ) d Where d.table_name Not In ( Select c.table_name From USER_TABLES c Where c.table_name Like 'T%' ) ORDER BY TABLE_NAME,COLUMN_ID,SQLTEXT

--ADD NEW COLUMN ACCORDING THE LATEST TABLE NAME SELECT 'ALTER TABLE '||TABLE_NAME||' ADD "'||COLUMN_NAME||'" '|| (CASE WHEN DATA_TYPE='NUMBER' THEN CASE WHEN DATA_PRECISION IS NULL THEN 'INTEGER' ELSE DATA_TYPE||'('||TO_CHAR(DATA_PRECISION)||','||TO_CHAR(DATA_SCALE)||')' END WHEN DATA_TYPE='NVARCHAR2' THEN DATA_TYPE||'('||TO_CHAR(DATA_LENGTH/2)||')' WHEN DATA_TYPE IN ('CHAR','VARCHAR2') THEN DATA_TYPE||'('||TO_CHAR(DATA_LENGTH)||')' WHEN DATA_TYPE IN ('DATE','BLOB','CLOB','LONG','NCLOB') THEN DATA_TYPE END)||' ;' SQLTEXT FROM USER_TAB_COLUMNS@REMOTEKGK A Where (a.table_name,a.column_name) Not In ( Select b.table_name,b.column_name From USER_TAB_COLS b Where b.table_name Like 'T%' ) And A.table_name Like 'T%' ORDER BY COLUMN_ID

--BASED THE COLUMN_NAME AND COLUMN_ID,NEED TO MODIFY THE COLUMN NAME --BUT IN FACT MOST SITUATION IT RESULT IN NEW COLUMN,SO IT IS NO USEFUL ....