浅谈postgresql数据库varchar、char、text的比较_PostgreSQL_

 using System; using System.Collections; using System.IO; using System.Text.RegularExpressions; namespace FullTextSearch.Common { /// 
 /// 中文分词器。 /// 
 public class ChineseParse { private static readonly ChineseWordsHashCountSet _countTable; static ChineseParse() { _countTable = new ChineseWordsHashCountSet(); InitFromFile("ChineseDictionary.txt"); } /// 
 /// 从指定的文件中初始化中文词语字典和字符串次数字典。 /// 
 /// 文件名 private static void InitFromFile(string fileName) { string path = Path.Combine(Directory.GetCurrentDirectory(), @"..\..\Common\", fileName); if (File.Exists(path)) { using (StreamReader sr = File.OpenText(path)) { string s = ""; while ((s = sr.ReadLine()) != null) { ChineseWordUnit _tempUnit = InitUnit(s); _countTable.InsertWord(_tempUnit.Word); } } } } /// 
 /// 将一个字符串解析为ChineseWordUnit。 /// 
 /// 字符串 /// 解析得到的ChineseWordUnit /// 4 /// 0 private static ChineseWordUnit InitUnit(string s) { var reg = new Regex(@"\s+"); string[] temp = reg.Split(s); //if (temp.Length != 2) //{ // throw new Exception("字符串解析错误：" + s); //} if (temp.Length != 1) { throw new Exception("字符串解析错误：" + s); } return new ChineseWordUnit(temp[0], Int32.Parse("1")); } /// 
 /// 分析输入的字符串，将其切割成一个个的词语。 /// 
 /// 待切割的字符串 /// 所切割得到的中文词语数组 public static string[] ParseChinese(string s) { int _length = s.Length; string _temp = String.Empty; var _words = new ArrayList(); for (int i = 0; i < s.Length;) { _temp = s.Substring(i, 1); if (_countTable.GetCount(_temp) > 1) { int j = 2; for (; i + j < s.Length + 1 && _countTable.GetCount(s.Substring(i, j)) > 0; j++) { } _temp = s.Substring(i, j - 1); i = i + j - 2; } i++; _words.Add(_temp); } var _tempStringArray = new string[_words.Count]; _words.CopyTo(_tempStringArray); return _tempStringArray; } } }

 using System.Collections; namespace FullTextSearch.Common { /// 
 /// 记录字符串出现在中文字典所录中文词语的前端的次数的字典类。如字符串"中"出现在"中国"的前端，则在字典中记录一个次数。 /// 
 public class ChineseWordsHashCountSet { /// 
 /// 记录字符串在中文词语中出现次数的Hashtable。键为特定的字符串，值为该字符串在中文词语中出现的次数。 /// 
 private readonly Hashtable _rootTable; /// 
 /// 类型初始化。 /// 
 public ChineseWordsHashCountSet() { _rootTable = new Hashtable(); } /// 
 /// 查询指定字符串出现在中文字典所录中文词语的前端的次数。 /// 
 /// 指定字符串 /// 字符串出现在中文字典所录中文词语的前端的次数。若为-1，表示不出现。 public int GetCount(string s) { if (!_rootTable.ContainsKey(s.Length)) { return -1; } var _tempTable = (Hashtable) _rootTable[s.Length]; if (!_tempTable.ContainsKey(s)) { return -1; } return (int) _tempTable[s]; } /// 
 /// 向次数字典中插入一个词语。解析该词语，插入次数字典。 /// 
 /// 所处理的字符串。 public void InsertWord(string s) { for (int i = 0; i < s.Length; i++) { string _s = s.Substring(0, i + 1); InsertSubString(_s); } } /// 
 /// 向次数字典中插入一个字符串的次数记录。 /// 
 /// 所插入的字符串。 private void InsertSubString(string s) { if (!_rootTable.ContainsKey(s.Length) && s.Length > 0) { var _newHashtable = new Hashtable(); _rootTable.Add(s.Length, _newHashtable); } var _tempTable = (Hashtable) _rootTable[s.Length]; if (!_tempTable.ContainsKey(s)) { _tempTable.Add(s, 1); } else { _tempTable[s] = (int) _tempTable[s] + 1; } } } }

 namespace FullTextSearch.Common { public struct ChineseWordUnit { private readonly int _power; private readonly string _word; /// 
 /// 结构初始化。 /// 
 /// 中文词语 /// 该词语的权重 public ChineseWordUnit(string word, int power) { _word = word; _power = power; } /// 
 /// 中文词语单元所对应的中文词。 /// 
 public string Word { get { return _word; } } /// 
 /// 该中文词语的权重。 /// 
 public int Power { get { return _power; } } } }

 using System; using System.Collections.Generic; using System.Data; using System.Drawing; using System.Windows.Forms; using FullTextSearch.Common; using Npgsql; namespace FullTextSearch { public partial class MainManager : Form { private readonly PostgreSQL pg = new PostgreSQL(); private readonly SQLquerys sqlQuerys = new SQLquerys(); private char analysisType; private string createConnString = ""; private DataSet dataSet = new DataSet(); private DataTable dataTable = new DataTable(); private char odabirAndOr; private char vrstaPretrazivanja; public MainManager() { InitializeComponent(); rbtn_AND.Checked = true; rbtnNeizmjenjeni.Checked = true; odabirAndOr = '*'; radioButton_Day.Checked = true; radioButton_Day.Checked = true; } private void Form1_Load(object sender, EventArgs e) { gb_unosPodataka.Enabled = false; groupBox_Search.Enabled = false; groupBox_Analysis.Enabled = false; button_Disconnect.Enabled = false; button_Pretrazi.BackColor = Color.WhiteSmoke; button_Disconnect.BackColor = Color.WhiteSmoke; button_unosTekstaUBazu.BackColor = Color.WhiteSmoke; button1.BackColor = Color.WhiteSmoke; } private void button_unosTekstaUBazu_Click(object sender, EventArgs e) { string searchTextBoxString = rTB_unosTextaUBazu.Text; if (searchTextBoxString != "") { pg.insertIntoTable(searchTextBoxString, pg.conn); MessageBox.Show(searchTextBoxString + " 添加到数据库!"); rTB_unosTextaUBazu.Clear(); } else { MessageBox.Show("不允许空数据!"); } } private void button_Pretrazi_Click(object sender, EventArgs e) { string stringToSearch; string sql; string highlitedText; string rank; string check; stringToSearch = txt_Search.Text.Trim(); var list = new List(ChineseParse.ParseChinese(stringToSearch)); ; sql = sqlQuerys.createSqlString(list, odabirAndOr, vrstaPretrazivanja); richTextBox1.Text = sql; check = sqlQuerys.testIfEmpty(stringToSearch); pg.insertIntoAnalysisTable(stringToSearch, pg.conn); pg.openConnection(); var command = new NpgsqlCommand(sql, pg.conn); NpgsqlDataReader reader = command.ExecuteReader(); int count = 0; linkLabel_Rezultat.Text = " "; while (reader.Read()) { highlitedText = reader[1].ToString(); rank = reader[3].ToString(); linkLabel_Rezultat.Text += highlitedText + "[" + rank + "]\n"; count++; } labelBrojac.Text = "找到的文件数量: " + count; pg.closeConnection(); } private void rbtn_AND_CheckedChanged(object sender, EventArgs e) { odabirAndOr = '*'; } private void rbtn_OR_CheckedChanged(object sender, EventArgs e) { odabirAndOr = '+'; } private void rbtnNeizmjenjeni_CheckedChanged(object sender, EventArgs e) { vrstaPretrazivanja = 'A'; } private void rbtn_Rijecnici_CheckedChanged(object sender, EventArgs e) { vrstaPretrazivanja = 'B'; } private void rbtn_Fuzzy_CheckedChanged(object sender, EventArgs e) { vrstaPretrazivanja = 'C'; } private void button_Connect_Click(object sender, EventArgs e) { if (connectMe()) { gb_unosPodataka.Enabled = true; groupBox_Search.Enabled = true; groupBox_Analysis.Enabled = true; textBox_Database.Enabled = false; textBox_IP.Enabled = false; textBox_Port.Enabled = false; textBox_Password.Enabled = false; textBox_UserID.Enabled = false; button_Connect.Enabled = false; button_Disconnect.Enabled = true; button_Pretrazi.BackColor = Color.SkyBlue; button_Disconnect.BackColor = Color.IndianRed; button_unosTekstaUBazu.BackColor = Color.MediumSeaGreen; button1.BackColor = Color.MediumSeaGreen; butt
                
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