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背景：我正在使用Java在Netbeans中。java sqlite autocommit慢
我正在讀取CSV文件中的行並將它們插入到SQLite數據庫中。非常基本的東西，我會想。從本網站和其他地方找到的例子中，我構建了以下代碼。它的工作原理，但我很驚訝，看它有多慢。花費3.95秒將46行加載到數據庫中！使用Netbeans Profiler，我可以看到它佔用了大部分時間3.7秒的autoCommit（）。
我在做什麼錯？或者，這僅僅是使用SQLite代替MySQL的代價？
public static void LoadJCNAClassesTable(Connection aConn, String strPath) throws SQLException{
String [] nextLine;
String strDivision;
String strClass;
String strNotes;
String strDescription;
Statement stat = aConn.createStatement();
stat.executeUpdate("drop table if exists JCNAClasses;");
String q = "create table JCNAClasses ('ID' INTEGER PRIMARY KEY AUTOINCREMENT, 'division' TEXT NOT NULL, 'class' TEXT NOT NULL UNIQUE, 'description' TEXT NOT NULL, 'note' TEXT NOT NULL, 'node' INTEGER NOT NULL);";
stat.executeUpdate(q);
CSVReader reader;
int iLine;
String JCNAClassesCSV = strPath + "\\JCNAClassesCsv.txt" ;
try {
reader = new CSVReader(new FileReader(JCNAClassesCSV));
iLine = 0;
while ((nextLine = reader.readNext()) != null) {
// nextLine[] is an array of values from the line
// System.out.println(nextLine[0] + nextLine[1]);
if (iLine > 0){
strDivision = nextLine[0];
strClass = nextLine[1];
strDescription= nextLine[2];
strNotes= nextLine[3];
PreparedStatement prep = aConn.prepareStatement("insert into JCNAClasses ('division', 'class', 'description', 'note', 'node') values (?, ?, ?, ?, ?);");
prep.setString(1, strDivision); // note that the comma seems not to be a problem
prep.setString(2,strClass);
prep.setString(3,strDescription);
prep.setString(4,strNotes);
prep.setInt(5,iLine);
prep.addBatch();
aConn.setAutoCommit(false);
prep.executeBatch();
aConn.setAutoCommit(true);
}
iLine++;
}
} catch (FileNotFoundException ex) {
Logger.getLogger(Entries.class.getName()).log(Level.SEVERE, null, ex);
}
catch (IOException ex) {
Logger.getLogger(Entries.class.getName()).log(Level.SEVERE, null, ex);
} catch (SQLException ex) {
Logger.getLogger(LoadSQLiteConcoursDatabase.class.getName()).log(Level.SEVERE, null, ex);
}
}
public static void LoadConcoursEntriesTable(Connection aConn, String strPath) throws SQLException{
String [] nextLine;
String strEntryName;
String strClass;
Integer intYear;
String strDescription;
String strOwnerFirst;
String strOwnerLast;
Integer intJCNA;
String strColor;
String strPlate;
Integer intNode;
Long intPersonnel_id;
Long intJaguar_id;
ResultSet generatedKeys;
String strStatus;
int intPersonnelNode;
ResultSet r;
CSVReader reader;
String q;
int iLine;
PreparedStatement prep;
ResultSet rs;
Statement stat = aConn.createStatement();
//
// Concourse Personnel Table: Owners, Judges, & Interested parties
//
stat.executeUpdate("drop table if exists ConcoursPersonnel");
// status: Owner = "O"; "J" = Judge; "OJ" = Owner & Judge; "IP" = Interested party, e.g., spouse, restorer
q = "create table ConcoursPersonnel ('personnel_id' INTEGER PRIMARY KEY AUTOINCREMENT , 'ownerfirst' TEXT NOT NULL, 'ownerlast' TEXT NOT NULL, 'jcna' INTEGER NOT NULL UNIQUE ON CONFLICT IGNORE, 'status' TEXT NOT NULL, 'node' INTEGER NOT NULL UNIQUE)";
stat.executeUpdate(q);
//
// Concours Jaguar Table
//
stat.executeUpdate("drop table if exists ConcoursJaguars");
q = "create table ConcoursJaguars ('jaguar_id' INTEGER PRIMARY KEY AUTOINCREMENT , 'class' TEXT NOT NULL, 'year' TEXT NOT NULL, 'description' TEXT NOT NULL, 'Color' TEXT, 'plate' TEXT, 'node' INTEGER NOT NULL UNIQUE)";
stat.executeUpdate(q);
//
// Entry Table (a Relationship or "link" between Personnel & Jaguars
//
stat.executeUpdate("drop table if exists ConcoursEntries");
q = "create table ConcoursEntries (entry_name TEXT NOT NULL, personnel_id INTEGER NOT NULL, jaguar_id INTEGER NOT NULL, UNIQUE (personnel_id, jaguar_id), FOREIGN KEY (personnel_id) REFERENCES ConcoursPersonnel (Personnel_ID), FOREIGN KEY (jaguar_id) REFERENCES ConcoursPersonnel (jaguar_id))";
stat.executeUpdate(q);
String EntriesCSV = strPath + "\\EntriesCsv.txt" ;
strStatus = "O"; // not in the CSV data so set to Owner
try {
reader = new CSVReader(new FileReader(EntriesCSV));
iLine = 0;
while ((nextLine = reader.readNext()) != null) {
// nextLine[] is an array of values from the line
// System.out.println(nextLine[0] + nextLine[1]);
if (iLine > 0){
strEntryName = nextLine[0];
strClass = nextLine[1];
intYear= Integer.parseInt(nextLine[2]);
strDescription= nextLine[3];
strOwnerFirst= nextLine[4];
strOwnerLast= nextLine[5];
intJCNA = Integer.parseInt(nextLine[6]) ;
strColor= nextLine[7];
strPlate= nextLine[8];
intNode= Integer.parseInt(nextLine[9]); // Since Jaguars are 1-to-1 with Entries this is used as Node number for both. However, it can't be used for Personnel Node
//
// Load Owners into Personnel Table
//
Statement s = aConn.createStatement();
r = s.executeQuery("SELECT COUNT(*) AS rowcount FROM ConcoursPersonnel");
r.next();
intPersonnelNode = r.getInt("rowcount") +1 ; // Assignes Personnel node numbers as a continuous sequence
prep = aConn.prepareStatement("insert into ConcoursPersonnel ('ownerfirst', 'ownerlast', 'jcna', 'status', 'node') values (?, ?, ?, ?, ?);");
//prep.setString(1, strEntryName); // note that the comma seems not to be a problem
prep.setString(1,strOwnerFirst);
prep.setString(2,strOwnerLast);
prep.setInt(3,intJCNA);
prep.setString(4,strStatus);
prep.setInt(5,intPersonnelNode);
prep.addBatch();
aConn.setAutoCommit(false); // starts transaction
prep.executeBatch();
aConn.setAutoCommit(true); // ends transaction
aConn.setAutoCommit(false); // starts transaction
stat = aConn.createStatement();
generatedKeys = stat.executeQuery("SELECT last_insert_rowid()");
intPersonnel_id = 0L; // won't be used
if (generatedKeys.next()) {
intPersonnel_id = generatedKeys.getLong(1);
}
else{
System.out.println("No Personnel ID found in LoadConcoursEntriesTable");
System.exit(-1);
}
aConn.setAutoCommit(true); // Commits transaction.
//
// Load Entry cars into the ConcoursJaguars table
//
prep = aConn.prepareStatement("insert into ConcoursJaguars ('class', 'year', 'description', 'color', 'plate', 'node') values (?, ?, ?, ?, ?, ?);");
prep.setString(1,strClass);
prep.setInt(2,intYear);
prep.setString(3,strDescription);
prep.setString(4,strColor);
prep.setString(5,strPlate);
prep.setInt(6,intNode); //
prep.addBatch();
aConn.setAutoCommit(false);
prep.executeBatch();
aConn.setAutoCommit(true);
q = "select jaguar_id from ConcoursJaguars where node == " + intNode + ";";
rs = stat.executeQuery(q);
intJaguar_id = rs.getLong("jaguar_id");
prep = aConn.prepareStatement("insert into ConcoursEntries (entry_name, personnel_id, jaguar_id) values (?, ?, ?);");
//prep.setString(1, strEntryName); // note that the comma seems not to be a problem
prep.setString(1,strEntryName);
prep.setLong(2,intPersonnel_id);
prep.setLong(3,intJaguar_id);
prep.addBatch();
aConn.setAutoCommit(false);
prep.executeBatch();
aConn.setAutoCommit(true);
}
iLine++;
}
} catch (FileNotFoundException ex) {
Logger.getLogger(Entries.class.getName()).log(Level.SEVERE, null, ex);
}
catch (IOException ex) {
Logger.getLogger(Entries.class.getName()).log(Level.SEVERE, null, ex);
} catch (SQLException ex) {
Logger.getLogger(LoadSQLiteConcoursDatabase.class.getName()).log(Level.SEVERE, null, ex);
}
}
這解決了建立單個表的問題，但我有其他關係表。特別是，我爲所謂的「參賽作品」（如在車展中）提供了一個CSV文件，其中每個參賽作品都有一位擁有者和一輛或多輛汽車。我想要在一張表中擁有汽車，在另一張表中擁有車主，並且有一個名爲「條目」的鏈接表。我在一個循環內部構建這3個表，遍歷Entries.csv文件。在這種情況下，我不能跳過Owner＆Car表中的executeBatch（），因爲如果它們沒有完成，我將不會有用於插入到Entries表中的外鍵。 – 2014-10-06 23:21:36
您可以將3個表格及其關係加上CSV文件的格式添加到您的問題中嗎？ – lcersly 2014-10-07 09:20:58
我添加了LoadConcoursEntriesTable（）的代碼，它創建人員表，Juguars表，然後創建條目鏈接表。 CVS文件的格式在代碼中很明顯，但如果您願意，我可以提供文件本身。它是41行。 – 2014-10-07 13:28:09