oracle中使用物化檢視實現表的同步
阿新 • • 發佈：2019-01-23
表的同步可以使用物化檢視來實現，可以是同庫的也可以是不同資料庫之間進行資料同步，建議在同庫的資料同步可以使用實時的同步，如果使用db link建議使用增量的重新整理方式，防止dblink導致原庫的效能急劇下降。
主要步驟：
1.在原表上建立物化檢視日誌
2.在建立目標表
3.建立與目標表同名的物化檢視日誌
1.建立原表和物化檢視日誌 SQL> conn bre/bre Connected. SQL> create table t1(id int,name varchar2(30)); Table created. SQL> alter table t1 add constraint pk_t1 primary key(id) using index; Table altered. SQL> create materialized view log on t1 with primary key; Materialized view log created.
<pre name="code" class="sql">2.建立目標表和物化檢視
注意這裡我建立是refresh fast on commit型別的物化檢視
SQL> create table t2 as select * from t1 where 1=2;
Table created.
SQL> CREATE MATERIALIZED VIEW t2 on prebuilt table refresh fast on commit as select * from t1;
Materialized view created.3.簡單測試 在t1插入一條資料，一提交t2即存在資料 SQL> insert into t1 values(1,'A'); 1 row created. SQL> commit; Commit complete. SQL> select * from t2; ID NAME ---------- ------------------------------ 1 A
4.ddl測試 通過測試我們發現物化檢視不支援ddl語句 我們給t1新增一個列和rename一個列 SQL> alter table t1 add sf int; Table altered. SQL> alter table t1 rename column name to names; Table altered. SQL> select * from t1; ID NAMES SF ---------- ------------------------------ ---------- 2 B SQL> select * from t2; ID NAME ---------- ------------------------------ 2 B SQL> insert into t1 values(3,'X',123); 1 row created. SQL> commit; Commit complete. SQL> select * from t1; ID NAMES SF ---------- ------------------------------ ---------- 2 B 3 X 123 SQL> select * from t2; ID NAME ---------- ------------------------------ 2 B 我們發現數據沒有過來，我們看一下物化檢視的定義和狀態 SQL> select dbms_metadata.get_ddl('MATERIALIZED_VIEW','T2') from dual; DBMS_METADATA.GET_DDL('MATERIALIZED_VIEW','T2') -------------------------------------------------------------------------------- CREATE MATERIALIZED VIEW "BRE"."T2" ("ID", "NAME") ON PREBUILT TABLE WITHOUT REDUCED PRECISION USING INDEX REFRESH FAST ON COMMIT WITH PRIMARY KEY USING DEFAULT LOCAL ROLLBACK SEGMENT USING ENFORCED CONSTRAINTS DISABLE QUERY REWRITE AS SELECT "T1"."ID" "ID","T1"."NAME" "NAME" FROM "T1" "T1" SQL> SELECT STALENESS from user_mviews; STALENESS ------------------- COMPILATION_ERROR 此時物化檢視為編譯錯誤。
5.重新建立一個demand物化檢視
SQL> CREATE MATERIALIZED VIEW t2 on prebuilt table refresh fast on demand as select * from t1;
Materialized view created.
SQL> select * from t2;
no rows selected
SQL> exec dbms_mview.refresh('T2','c'); --手工全量重新整理
PL/SQL procedure successfully completed.
SQL> select * from t2;
ID NAMES SF
---------- ------------------------------ ----------
2 B
3 X 123
SQL> insert into t1 values(4,'Y',88);
1 row created.
SQL> commit;
Commit complete.
SQL> select * from t2;
ID NAMES SF
---------- ------------------------------ ----------
2 B
3 X 123
SQL> exec dbms_mview.refresh('T2','f'); --手工增量重新整理
PL/SQL procedure successfully completed.
SQL> select * from t2;
ID NAMES SF
---------- ------------------------------ ----------
2 B
3 X 123
4 Y 886.建立物化檢視的語句
官方文件：
http://docs.oracle.com/database/121/SQLRF/statements_6002.htm#SQLRF01302
CREATE MATERIALIZED VIEW [ schema. ] materialized_view
[ OF [ schema. ] object_type ]
[ ( { scoped_table_ref_constraint
| column_alias [ENCRYPT [encryption_spec]]
}
[, { scoped_table_ref_constraint
| column_alias [ENCRYPT [encryption_spec]]
}
]...
)
]
{ ON PREBUILT TABLE
[ { WITH | WITHOUT } REDUCED PRECISION ]
| physical_properties materialized_view_props
}
[ USING INDEX
[ physical_attributes_clause
| TABLESPACE tablespace
]...
| USING NO INDEX
]
[ create_mv_refresh ]
[ FOR UPDATE ]
[ evaluation_edition_clause ]
[ query_rewrite_clause ]
AS subquery ;
7.建立物化檢視日誌的語句
官方文件：
http://docs.oracle.com/database/121/SQLRF/statements_6003.htm#SQLRF01303
CREATE MATERIALIZED VIEW LOG ON [ schema. ] table
[ physical_attributes_clause
| TABLESPACE tablespace
| logging_clause
| { CACHE | NOCACHE }
]...
[ parallel_clause ]
[ table_partitioning_clauses ]
[ WITH [ { OBJECT ID
| PRIMARY KEY
| ROWID
| SEQUENCE
| COMMIT SCN
}
[ { , OBJECT ID
| , PRIMARY KEY
| , ROWID
| , SEQUENCE
| , COMMIT SCN
}
]... ]
(column [, column ]...)
[ new_values_clause ]
] [ mv_log_purge_clause ]
;