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package main
import (
"database/sql"
"fmt"
"log"
"os"
"strings"
"github.com/mattn/go-sqlite3"
)
func createBulkInsertQuery(n int, start int) (query string, args []interface{}) {
values := make([]string, n)
args = make([]interface{}, n*2)
pos := 0
for i := 0; i < n; i++ {
values[i] = "(?, ?)"
args[pos] = start + i
args[pos+1] = fmt.Sprintf("こんにちは世界%03d", i)
pos += 2
}
query = fmt.Sprintf(
"insert into foo(id, name) values %s",
strings.Join(values, ", "),
)
return
}
func bulkInsert(db *sql.DB, query string, args []interface{}) (err error) {
stmt, err := db.Prepare(query)
if err != nil {
return
}
_, err = stmt.Exec(args...)
if err != nil {
return
}
return
}
func main() {
var sqlite3conn *sqlite3.SQLiteConn
sql.Register("sqlite3_with_limit", &sqlite3.SQLiteDriver{
ConnectHook: func(conn *sqlite3.SQLiteConn) error {
sqlite3conn = conn
return nil
},
})
os.Remove("./foo.db")
db, err := sql.Open("sqlite3_with_limit", "./foo.db")
if err != nil {
log.Fatal(err)
}
defer db.Close()
sqlStmt := `
create table foo (id integer not null primary key, name text);
delete from foo;
`
_, err = db.Exec(sqlStmt)
if err != nil {
log.Printf("%q: %s\n", err, sqlStmt)
return
}
if sqlite3conn == nil {
log.Fatal("not set sqlite3 connection")
}
limitVariableNumber := sqlite3conn.GetLimit(sqlite3.SQLITE_LIMIT_VARIABLE_NUMBER)
log.Printf("default SQLITE_LIMIT_VARIABLE_NUMBER: %d", limitVariableNumber)
num := 400
query, args := createBulkInsertQuery(num, 0)
err = bulkInsert(db, query, args)
if err != nil {
log.Fatal(err)
}
smallLimitVariableNumber := 100
sqlite3conn.SetLimit(sqlite3.SQLITE_LIMIT_VARIABLE_NUMBER, smallLimitVariableNumber)
limitVariableNumber = sqlite3conn.GetLimit(sqlite3.SQLITE_LIMIT_VARIABLE_NUMBER)
log.Printf("updated SQLITE_LIMIT_VARIABLE_NUMBER: %d", limitVariableNumber)
query, args = createBulkInsertQuery(num, num)
err = bulkInsert(db, query, args)
if err != nil {
if err != nil {
log.Printf("expect failed since SQLITE_LIMIT_VARIABLE_NUMBER is too small: %v", err)
}
}
bigLimitVariableNumber := 999999
sqlite3conn.SetLimit(sqlite3.SQLITE_LIMIT_VARIABLE_NUMBER, bigLimitVariableNumber)
limitVariableNumber = sqlite3conn.GetLimit(sqlite3.SQLITE_LIMIT_VARIABLE_NUMBER)
log.Printf("set SQLITE_LIMIT_VARIABLE_NUMBER: %d", bigLimitVariableNumber)
log.Printf("updated SQLITE_LIMIT_VARIABLE_NUMBER: %d", limitVariableNumber)
query, args = createBulkInsertQuery(500, num+num)
err = bulkInsert(db, query, args)
if err != nil {
if err != nil {
log.Fatal(err)
}
}
log.Println("no error if SQLITE_LIMIT_VARIABLE_NUMBER > 999")
}
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