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135 lines
3.5 KiB
Go
135 lines
3.5 KiB
Go
/*
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Package sqlite3 provides interface to SQLite3 databases.
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This works as a driver for database/sql.
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Installation
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go get github.com/mattn/go-sqlite3
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# Supported Types
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Currently, go-sqlite3 supports the following data types.
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+------------------------------+
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|go | sqlite3 |
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|----------|-------------------|
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|nil | null |
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|int | integer |
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|int64 | integer |
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|float64 | float |
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|bool | integer |
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|[]byte | blob |
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|string | text |
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|time.Time | timestamp/datetime|
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+------------------------------+
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# SQLite3 Extension
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You can write your own extension module for sqlite3. For example, below is an
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extension for a Regexp matcher operation.
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#include <pcre.h>
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#include <string.h>
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#include <stdio.h>
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#include <sqlite3ext.h>
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SQLITE_EXTENSION_INIT1
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static void regexp_func(sqlite3_context *context, int argc, sqlite3_value **argv) {
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if (argc >= 2) {
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const char *target = (const char *)sqlite3_value_text(argv[1]);
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const char *pattern = (const char *)sqlite3_value_text(argv[0]);
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const char* errstr = NULL;
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int erroff = 0;
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int vec[500];
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int n, rc;
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pcre* re = pcre_compile(pattern, 0, &errstr, &erroff, NULL);
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rc = pcre_exec(re, NULL, target, strlen(target), 0, 0, vec, 500);
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if (rc <= 0) {
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sqlite3_result_error(context, errstr, 0);
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return;
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}
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sqlite3_result_int(context, 1);
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}
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}
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#ifdef _WIN32
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__declspec(dllexport)
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#endif
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int sqlite3_extension_init(sqlite3 *db, char **errmsg,
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const sqlite3_api_routines *api) {
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SQLITE_EXTENSION_INIT2(api);
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return sqlite3_create_function(db, "regexp", 2, SQLITE_UTF8,
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(void*)db, regexp_func, NULL, NULL);
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}
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It needs to be built as a so/dll shared library. And you need to register
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the extension module like below.
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sql.Register("sqlite3_with_extensions",
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&sqlite3.SQLiteDriver{
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Extensions: []string{
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"sqlite3_mod_regexp",
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},
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})
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Then, you can use this extension.
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rows, err := db.Query("select text from mytable where name regexp '^golang'")
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# Connection Hook
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You can hook and inject your code when the connection is established by setting
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ConnectHook to get the SQLiteConn.
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sql.Register("sqlite3_with_hook_example",
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&sqlite3.SQLiteDriver{
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ConnectHook: func(conn *sqlite3.SQLiteConn) error {
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sqlite3conn = append(sqlite3conn, conn)
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return nil
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},
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})
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You can also use database/sql.Conn.Raw (Go >= 1.13):
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conn, err := db.Conn(context.Background())
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// if err != nil { ... }
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defer conn.Close()
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err = conn.Raw(func (driverConn any) error {
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sqliteConn := driverConn.(*sqlite3.SQLiteConn)
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// ... use sqliteConn
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})
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// if err != nil { ... }
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# Go SQlite3 Extensions
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If you want to register Go functions as SQLite extension functions
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you can make a custom driver by calling RegisterFunction from
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ConnectHook.
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regex = func(re, s string) (bool, error) {
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return regexp.MatchString(re, s)
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}
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sql.Register("sqlite3_extended",
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&sqlite3.SQLiteDriver{
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ConnectHook: func(conn *sqlite3.SQLiteConn) error {
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return conn.RegisterFunc("regexp", regex, true)
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},
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})
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You can then use the custom driver by passing its name to sql.Open.
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var i int
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conn, err := sql.Open("sqlite3_extended", "./foo.db")
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if err != nil {
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panic(err)
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}
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err = db.QueryRow(`SELECT regexp("foo.*", "seafood")`).Scan(&i)
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if err != nil {
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panic(err)
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}
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See the documentation of RegisterFunc for more details.
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*/
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package sqlite3
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