前一阵写了Oracle基本数据类型存储格式浅析，对各种数量类型的存储进行了简单的描述，而后又写了一篇repare包修复坏块，其中自己写了一个程序包来恢复DUMP后的数据。但是那个程序包主要是针对repare包生成的结果的，因此通用性不好。
这篇文章将那个程序包修改并简化，变为一个函数。下面给出这个函数的实现和使用例子：
代码：——
SQL> CREATE OR REPLACE FUNCTION F_GET_FROM_DUMP
2 (
3 P_DUMP IN VARCHAR2,
4 P_TYPE IN VARCHAR2
5 )
6 RETURN VARCHAR2 AS
7 V_LENGTH_STR VARCHAR2(10);
8 V_LENGTH NUMBER DEFAULT 7;
9 V_DUMP_ROWID VARCHAR2(30000);
10
11 V_DATE_STR VARCHAR2(100);
12 TYPE T_DATE IS TABLE OF NUMBER INDEX BY BINARY_INTEGER;
13 V_DATE T_DATE;
14
15 FUNCTION F_ADD_PREFIX_ZERO (P_STR IN VARCHAR2, P_POSITION IN NUMBER) RETURN VARCHAR2
16 AS
17 V_STR VARCHAR2(30000) := P_STR;
18 V_POSITION NUMBER := P_POSITION;
19 V_STR_PART VARCHAR2(2);
20 V_RETURN VARCHAR2(30000);
21 BEGIN
22 WHILE (V_POSITION != 0) LOOP
23 V_STR_PART := SUBSTR(V_STR, 1, V_POSITION - 1);
24 V_STR := SUBSTR(V_STR, V_POSITION + 1);
25
26 IF V_POSITION = 2 THEN
27 V_RETURN := V_RETURN || '0' || V_STR_PART;
28 ELSIF V_POSITION = 3 THEN
29 V_RETURN := V_RETURN || V_STR_PART;
30 ELSE
31 RAISE_APPLICATION_ERROR(-20002, 'DUMP ERROR CHECK THE INPUT ROWID');
32 END IF;
33
34 V_POSITION := INSTR(V_STR, ',');
35 END LOOP;
36 RETURN REPLACE(V_RETURN , ',');
37 END F_ADD_PREFIX_ZERO;
38
39 BEGIN
40 IF SUBSTR(P_DUMP, 1, 3) = 'Typ' THEN
41 V_DUMP_ROWID := SUBSTR(P_DUMP, INSTR(P_DUMP, ':') + 2);
42 ELSE
43 V_DUMP_ROWID := P_DUMP;
44 END IF;
45
46 IF P_TYPE = 'VARCHAR2' OR P_TYPE = 'CHAR' THEN
47
48 V_DUMP_ROWID :=F_ADD_PREFIX_ZERO(V_DUMP_ROWID || ',', INSTR(V_DUMP_ROWID, ','));
49
50 RETURN(UTL_RAW.CAST_TO_VARCHAR2(V_DUMP_ROWID));
51
52 ELSIF P_TYPE = 'NUMBER' THEN
53
54 V_DUMP_ROWID :=F_ADD_PREFIX_ZERO(V_DUMP_ROWID || ',', INSTR(V_DUMP_ROWID, ','));
55
56 RETURN(TO_CHAR(UTL_RAW.CAST_TO_NUMBER(V_DUMP_ROWID)));
57
58 ELSIF P_TYPE = 'DATE' THEN
59
60 V_DUMP_ROWID := ',' || V_DUMP_ROWID || ',';
61
62 FOR I IN 1..7 LOOP
63 V_DATE(I) := TO_NUMBER(SUBSTR(V_DUMP_ROWID, INSTR(V_DUMP_ROWID, ',', 1, I) + 1,
64 INSTR(V_DUMP_ROWID, ',', 1, I + 1) - INSTR(V_DUMP_ROWID, ',', 1, I) - 1), 'XXX');
65 END LOOP;
66
67 V_DATE(1) := V_DATE(1) - 100;
68 V_DATE(2) := V_DATE(2) - 100;
69
70 IF ((V_DATE(1) < 0) OR (V_DATE(2) < 0)) THEN
71 V_DATE_STR := '-' || LTRIM(TO_CHAR(ABS(V_DATE(1)), '00')) || LTRIM(TO_CHAR(ABS(V_DATE(2)), '
00'));
72 ELSE
73 V_DATE_STR := LTRIM(TO_CHAR(ABS(V_DATE(1)), '00')) || LTRIM(TO_CHAR(ABS(V_DATE(2)),'00'));
74 END IF;
75
76 V_DATE_STR := V_DATE_STR || '-' || TO_CHAR(V_DATE(3)) || '-' || TO_CHAR(V_DATE(4)) || ' ' ||
77 TO_CHAR(V_DATE(5) - 1) || ':' || TO_CHAR(V_DATE(6) - 1) || ':' || TO_CHAR(V_DATE(7) - 1);
78 RETURN (V_DATE_STR);
79
80 ELSIF ((P_TYPE LIKE 'TIMESTAMP(_)') OR (P_TYPE = 'TIMESTAMP')) THEN
81
82 V_DUMP_ROWID := ',' || V_DUMP_ROWID || ',';
83
84 FOR I IN 1..11 LOOP
85 V_DATE(I) := TO_NUMBER(SUBSTR(V_DUMP_ROWID, INSTR(V_DUMP_ROWID, ',', 1, I) + 1,
86 INSTR(V_DUMP_ROWID, ',', 1, I + 1) - INSTR(V_DUMP_ROWID, ',', 1, I) - 1), 'XXX');
87 END LOOP;
88
89 V_DATE(1) := V_DATE(1) - 100;
90 V_DATE(2) := V_DATE(2) - 100;
91
92 IF ((V_DATE(1) < 0) OR (V_DATE(2) < 0)) THEN
93 V_DATE_STR := '-' || LTRIM(TO_CHAR(ABS(V_DATE(1)), '00')) || LTRIM(TO_CHAR(ABS(V_DATE(2)), '
00'));
94 ELSE
95 V_DATE_STR := LTRIM(TO_CHAR(ABS(V_DATE(1)), '00')) || LTRIM(TO_CHAR(ABS(V_DATE(2)),'00'));
96 END IF;
97
98 V_DATE_STR := V_DATE_STR || '-' || TO_CHAR(V_DATE(3)) || '-' || TO_CHAR(V_DATE(4)) || ' ' ||
99 TO_CHAR(V_DATE(5) - 1) || ':' || TO_CHAR(V_DATE(6) - 1) || ':' || TO_CHAR(V_DATE(7) - 1) ||
'.' ||
100 SUBSTR(TO_CHAR(V_DATE(8) * POWER(256, 3) + V_DATE(9) * POWER(256, 2) + V_DATE(10) * 256 + V_
DATE(11)),
101 1, NVL(TO_NUMBER(SUBSTR(P_TYPE, 11, 1)), 6));
102 RETURN (V_DATE_STR);
103
104 ELSIF P_TYPE = 'RAW' THEN
105
106 V_DUMP_ROWID :=F_ADD_PREFIX_ZERO(V_DUMP_ROWID || ',', INSTR(V_DUMP_ROWID, ','));
107
108 RETURN(V_DUMP_ROWID);
109
110 ELSIF P_TYPE = 'ROWID' THEN
111
112 V_DUMP_ROWID :=F_ADD_PREFIX_ZERO(V_DUMP_ROWID || ',', INSTR(V_DUMP_ROWID, ','));
113 RETURN (DBMS_ROWID.ROWID_CREATE(
114 1,
115 TO_NUMBER(SUBSTR(V_DUMP_ROWID, 1, 8), 'XXXXXXXXXXX'),
116 TRUNC(TO_NUMBER(SUBSTR(V_DUMP_ROWID, 9, 4), 'XXXXXX')/64),
117 TO_NUMBER(MOD(TO_NUMBER(SUBSTR(V_DUMP_ROWID, 9, 4), 'XXXXXX'), 64) ||
118 TO_NUMBER(SUBSTR(V_DUMP_ROWID, 13, 4), 'XXXXXXXXXXX')),
119 TO_NUMBER(SUBSTR(V_DUMP_ROWID, 17, 4), 'XXXXXX')));
120
121 ELSE
122 RAISE_APPLICATION_ERROR(-20001, 'TYPE NOT VALID OR CAN''T TRANSALTE ' || P_TYPE || ' TYPE');
123 END IF;
124
125 END;
126 /
函数已创建。
SQL> SELECT F_GET_FROM_DUMP(DUMP(2342.231, 16), 'NUMBER') FROM DUAL;
F_GET_FROM_DUMP(DUMP(2342.231,16),'NUMBER')
--------------------------------------------
2342.231
SQL> SELECT F_GET_FROM_DUMP(DUMP(-0.00234, 16), 'NUMBER') FROM DUAL;
F_GET_FROM_DUMP(DUMP(-0.00234,16),'NUMBER')
------------------------------