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1 /* | |
2 ** 2009 November 10 | |
3 ** | |
4 ** The author disclaims copyright to this source code. In place of | |
5 ** a legal notice, here is a blessing: | |
6 ** | |
7 ** May you do good and not evil. | |
8 ** May you find forgiveness for yourself and forgive others. | |
9 ** May you share freely, never taking more than you give. | |
10 ** | |
11 ************************************************************************* | |
12 ** | |
13 ** This is the C-language interface definition for the "intarray" or | |
14 ** integer array virtual table for SQLite. | |
15 ** | |
16 ** The intarray virtual table is designed to facilitate using an | |
17 ** array of integers as the right-hand side of an IN operator. So | |
18 ** instead of doing a prepared statement like this: | |
19 ** | |
20 ** SELECT * FROM table WHERE x IN (?,?,?,...,?); | |
21 ** | |
22 ** And then binding indivdual integers to each of ? slots, a C-language | |
23 ** application can create an intarray object (named "ex1" in the following | |
24 ** example), prepare a statement like this: | |
25 ** | |
26 ** SELECT * FROM table WHERE x IN ex1; | |
27 ** | |
28 ** Then bind an ordinary C/C++ array of integer values to the ex1 object | |
29 ** to run the statement. | |
30 ** | |
31 ** USAGE: | |
32 ** | |
33 ** One or more intarray objects can be created as follows: | |
34 ** | |
35 ** sqlite3_intarray *p1, *p2, *p3; | |
36 ** sqlite3_intarray_create(db, "ex1", &p1); | |
37 ** sqlite3_intarray_create(db, "ex2", &p2); | |
38 ** sqlite3_intarray_create(db, "ex3", &p3); | |
39 ** | |
40 ** Each call to sqlite3_intarray_create() generates a new virtual table | |
41 ** module and a singleton of that virtual table module in the TEMP | |
42 ** database. Both the module and the virtual table instance use the | |
43 ** name given by the second parameter. The virtual tables can then be | |
44 ** used in prepared statements: | |
45 ** | |
46 ** SELECT * FROM t1, t2, t3 | |
47 ** WHERE t1.x IN ex1 | |
48 ** AND t2.y IN ex2 | |
49 ** AND t3.z IN ex3; | |
50 ** | |
51 ** Each integer array is initially empty. New arrays can be bound to | |
52 ** an integer array as follows: | |
53 ** | |
54 ** sqlite3_int64 a1[] = { 1, 2, 3, 4 }; | |
55 ** sqlite3_int64 a2[] = { 5, 6, 7, 8, 9, 10, 11 }; | |
56 ** sqlite3_int64 *a3 = sqlite3_malloc( 100*sizeof(sqlite3_int64) ); | |
57 ** // Fill in content of a3[] | |
58 ** sqlite3_intarray_bind(p1, 4, a1, 0); | |
59 ** sqlite3_intarray_bind(p2, 7, a2, 0); | |
60 ** sqlite3_intarray_bind(p3, 100, a3, sqlite3_free); | |
61 ** | |
62 ** A single intarray object can be rebound multiple times. But do not | |
63 ** attempt to change the bindings of an intarray while it is in the middle | |
64 ** of a query. | |
65 ** | |
66 ** The array that holds the integers is automatically freed by the function | |
67 ** in the fourth parameter to sqlite3_intarray_bind() when the array is no | |
68 ** longer needed. The application must not change the intarray values | |
69 ** while an intarray is in the middle of a query. | |
70 ** | |
71 ** The intarray object is automatically destroyed when its corresponding | |
72 ** virtual table is dropped. Since the virtual tables are created in the | |
73 ** TEMP database, they are automatically dropped when the database connection | |
74 ** closes so the application does not normally need to take any special | |
75 ** action to free the intarray objects. | |
76 */ | |
77 #include "sqlite3.h" | |
78 #ifndef _INTARRAY_H_ | |
79 #define _INTARRAY_H_ | |
80 | |
81 /* | |
82 ** Make sure we can call this stuff from C++. | |
83 */ | |
84 #ifdef __cplusplus | |
85 extern "C" { | |
86 #endif | |
87 | |
88 /* | |
89 ** An sqlite3_intarray is an abstract type to stores an instance of | |
90 ** an integer array. | |
91 */ | |
92 typedef struct sqlite3_intarray sqlite3_intarray; | |
93 | |
94 /* | |
95 ** Invoke this routine to create a specific instance of an intarray object. | |
96 ** The new intarray object is returned by the 3rd parameter. | |
97 ** | |
98 ** Each intarray object corresponds to a virtual table in the TEMP table | |
99 ** with a name of zName. | |
100 ** | |
101 ** Destroy the intarray object by dropping the virtual table. If not done | |
102 ** explicitly by the application, the virtual table will be dropped implicitly | |
103 ** by the system when the database connection is closed. | |
104 */ | |
105 SQLITE_API int sqlite3_intarray_create( | |
106 sqlite3 *db, | |
107 const char *zName, | |
108 sqlite3_intarray **ppReturn | |
109 ); | |
110 | |
111 /* | |
112 ** Bind a new array array of integers to a specific intarray object. | |
113 ** | |
114 ** The array of integers bound must be unchanged for the duration of | |
115 ** any query against the corresponding virtual table. If the integer | |
116 ** array does change or is deallocated undefined behavior will result. | |
117 */ | |
118 SQLITE_API int sqlite3_intarray_bind( | |
119 sqlite3_intarray *pIntArray, /* The intarray object to bind to */ | |
120 int nElements, /* Number of elements in the intarray */ | |
121 sqlite3_int64 *aElements, /* Content of the intarray */ | |
122 void (*xFree)(void*) /* How to dispose of the intarray when done */ | |
123 ); | |
124 | |
125 #ifdef __cplusplus | |
126 } /* End of the 'extern "C"' block */ | |
127 #endif | |
128 #endif /* _INTARRAY_H_ */ | |
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