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C# 封装 System.Data.SQLite

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参考1:

关于如何使用System.Data.SQLite的入门：

http://www.dreamincode.net/forums/topic/157830-using-sqlite-with-c%23/

 

技术分享 技术分享 
                  1
                using
                 System;

                  2
                using
                 System.Collections.Generic;

                  3
                using
                 System.Data;

                  4
                using
                 System.Data.SQLite;

                  5
                using
                 System.Globalization;

                  6
                using
                 System.Linq;

                  7
                using
                 System.Windows.Forms;

                  8
                  9
                namespace
                 Simple_Disk_Catalog

                 10
                {

                 11
                public
                class
                 SQLiteDatabase

                 12
                    {

                 13
                        String DBConnection;

                 14
                 15
                private
                readonly
                 SQLiteTransaction _sqLiteTransaction;

                 16
                 17
                private
                readonly
                 SQLiteConnection _sqLiteConnection;

                 18
                 19
                private
                readonly
                bool
                 _transaction;

                 20
                 21
                ///
                <summary>
                 22
                ///
                     Default Constructor for SQLiteDatabase Class.

                 23
                ///
                </summary>
                 24
                ///
                <param name="transaction">
                Allow programmers to insert, update and delete values in one transaction
                </param>
                 25
                public SQLiteDatabase(bool transaction = false)
 26        {
 27             _transaction = transaction;
 28             DBConnection = "Data Source=recipes.s3db";
 29if (transaction)
 30            {
 31                 _sqLiteConnection = new SQLiteConnection(DBConnection);
 32                _sqLiteConnection.Open();
 33                 _sqLiteTransaction = _sqLiteConnection.BeginTransaction();
 34            }
 35        }
 36 37///<summary> 38///     Single Param Constructor for specifying the DB file.
 39///</summary> 40///<param name="inputFile">The File containing the DB</param> 41public SQLiteDatabase(String inputFile)
 42        {
 43             DBConnection = String.Format("Data Source={0}", inputFile);
 44        }
 45 46///<summary> 47///     Commit transaction to the database.
 48///</summary> 49publicvoid CommitTransaction()
 50        {
 51            _sqLiteTransaction.Commit();
 52            _sqLiteTransaction.Dispose();
 53            _sqLiteConnection.Close();
 54            _sqLiteConnection.Dispose();
 55        }
 56 57///<summary> 58///     Single Param Constructor for specifying advanced connection options.
 59///</summary> 60///<param name="connectionOpts">A dictionary containing all desired options and their values</param> 61public SQLiteDatabase(Dictionary<String, String> connectionOpts)
 62        {
 63             String str = connectionOpts.Aggregate("", (current, row) => current + String.Format("{0}={1}; ", row.Key, row.Value));
 64             str = str.Trim().Substring(0, str.Length - 1);
 65             DBConnection = str;
 66        }
 67 68///<summary> 69///     Allows the programmer to create new database file.
 70///</summary> 71///<param name="filePath">Full path of a new database file.</param> 72///<returns>true or false to represent success or failure.</returns> 73publicstaticbool CreateDB(string filePath)
 74        {
 75try 76            {
 77                SQLiteConnection.CreateFile(filePath);
 78returntrue;
 79            }
 80catch (Exception e)
 81            {
 82                MessageBox.Show(e.Message, e.GetType().ToString(), MessageBoxButtons.OK, MessageBoxIcon.Error);
 83returnfalse;
 84            }
 85        }
 86 87///<summary> 88///     Allows the programmer to run a query against the Database.
 89///</summary> 90///<param name="sql">The SQL to run</param> 91///<param name="allowDBNullColumns">Allow null value for columns in this collection.</param> 92///<returns>A DataTable containing the result set.</returns> 93public DataTable GetDataTable(string sql, IEnumerable<string> allowDBNullColumns = null)
 94        {
 95var dt = new DataTable();
 96if (allowDBNullColumns != null)
 97foreach (var s in allowDBNullColumns)
 98                {
 99                    dt.Columns.Add(s);
100                     dt.Columns[s].AllowDBNull = true;
101                }
102try103            {
104var cnn = new SQLiteConnection(DBConnection);
105                cnn.Open();
106var mycommand = new SQLiteCommand(cnn) {CommandText = sql};
107var reader = mycommand.ExecuteReader();
108                dt.Load(reader);
109                reader.Close();
110                cnn.Close();
111            }
112catch (Exception e)
113            {
114thrownew Exception(e.Message);
115            }
116return dt;
117        }
118119publicstring RetrieveOriginal(string value)
120        {
121return122                 value.Replace("&amp;", "&").Replace("&lt;", "<").Replace("&gt;", "<").Replace("&quot;", "\"").Replace(
123"&apos;", "‘");
124        }
125126///<summary>127///     Allows the programmer to interact with the database for purposes other than a query.
128///</summary>129///<param name="sql">The SQL to be run.</param>130///<returns>An Integer containing the number of rows updated.</returns>131publicint ExecuteNonQuery(string sql)
132        {
133if (!_transaction)
134            {
135var cnn = new SQLiteConnection(DBConnection);
136                cnn.Open();
137var mycommand = new SQLiteCommand(cnn) {CommandText = sql};
138var rowsUpdated = mycommand.ExecuteNonQuery();
139                cnn.Close();
140return rowsUpdated;
141            }
142else143            {
144var mycommand = new SQLiteCommand(_sqLiteConnection) { CommandText = sql };
145return mycommand.ExecuteNonQuery();
146            }
147        }
148149///<summary>150///     Allows the programmer to retrieve single items from the DB.
151///</summary>152///<param name="sql">The query to run.</param>153///<returns>A string.</returns>154publicstring ExecuteScalar(string sql)
155        {
156if (!_transaction)
157            {
158var cnn = new SQLiteConnection(DBConnection);
159                cnn.Open();
160var mycommand = new SQLiteCommand(cnn) {CommandText = sql};
161var value = mycommand.ExecuteScalar();
162                cnn.Close();
163return value != null ? value.ToString() : "";
164            }
165else166            {
167var sqLiteCommand = new SQLiteCommand(_sqLiteConnection) { CommandText = sql };
168var value = sqLiteCommand.ExecuteScalar();
169return value != null ? value.ToString() : "";
170            }
171        }
172173///<summary>174///     Allows the programmer to easily update rows in the DB.
175///</summary>176///<param name="tableName">The table to update.</param>177///<param name="data">A dictionary containing Column names and their new values.</param>178///<param name="where">The where clause for the update statement.</param>179///<returns>A boolean true or false to signify success or failure.</returns>180publicbool Update(String tableName, Dictionary<String, String> data, String where)
181        {
182             String vals = "";
183             Boolean returnCode = true;
184if (data.Count >= 1)
185            {
186                 vals = data.Aggregate(vals, (current, val) => current + String.Format(" {0} = ‘{1}‘,", val.Key.ToString(CultureInfo.InvariantCulture), val.Value.ToString(CultureInfo.InvariantCulture)));
187                 vals = vals.Substring(0, vals.Length - 1);
188            }
189try190            {
191                 ExecuteNonQuery(String.Format("update {0} set {1} where {2};", tableName, vals, where));
192            }
193catch194            {
195                 returnCode = false;
196            }
197return returnCode;
198        }
199200///<summary>201///     Allows the programmer to easily delete rows from the DB.
202///</summary>203///<param name="tableName">The table from which to delete.</param>204///<param name="where">The where clause for the delete.</param>205///<returns>A boolean true or false to signify success or failure.</returns>206publicbool Delete(String tableName, String where)
207        {
208             Boolean returnCode = true;
209try210            {
211                 ExecuteNonQuery(String.Format("delete from {0} where {1};", tableName, where));
212            }
213catch (Exception fail)
214            {
215                MessageBox.Show(fail.Message, fail.GetType().ToString(), MessageBoxButtons.OK, MessageBoxIcon.Error);
216                 returnCode = false;
217            }
218return returnCode;
219        }
220221///<summary>222///     Allows the programmer to easily insert into the DB
223///</summary>224///<param name="tableName">The table into which we insert the data.</param>225///<param name="data">A dictionary containing the column names and data for the insert.</param>226///<returns>returns last inserted row id if it‘s value is zero than it means failure.</returns>227publiclong Insert(String tableName, Dictionary<String, String> data)
228        {
229             String columns = "";
230             String values = "";
231            String value;
232foreach (KeyValuePair<String, String> val in data)
233            {
234                 columns += String.Format(" {0},", val.Key.ToString(CultureInfo.InvariantCulture));
235                 values += String.Format(" ‘{0}‘,", val.Value);
236            }
237             columns = columns.Substring(0, columns.Length - 1);
238             values = values.Substring(0, values.Length - 1);
239try240            {
241if (!_transaction)
242                {
243var cnn = new SQLiteConnection(DBConnection);
244                    cnn.Open();
245var sqLiteCommand = new SQLiteCommand(cnn)
246                                        {
247                                             CommandText =
248                                                 String.Format("insert into {0}({1}) values({2});", tableName, columns,
249                                                              values)
250                                        };
251                    sqLiteCommand.ExecuteNonQuery();
252                     sqLiteCommand = new SQLiteCommand(cnn) { CommandText = "SELECT last_insert_rowid()" };
253                     value = sqLiteCommand.ExecuteScalar().ToString();
254                }
255else256                {
257                     ExecuteNonQuery(String.Format("insert into {0}({1}) values({2});", tableName, columns, values));
258                     value = ExecuteScalar("SELECT last_insert_rowid()");
259                }
260            }
261catch (Exception fail)
262            {
263                MessageBox.Show(fail.Message, fail.GetType().ToString(), MessageBoxButtons.OK, MessageBoxIcon.Error);
264return0;
265            }
266returnlong.Parse(value);
267        }
268269///<summary>270///     Allows the programmer to easily delete all data from the DB.
271///</summary>272///<returns>A boolean true or false to signify success or failure.</returns>273publicbool ClearDB()
274        {
275try276            {
277var tables = GetDataTable("select NAME from SQLITE_MASTER where type=‘table‘ order by NAME;");
278foreach (DataRow table in tables.Rows)
279                {
280                     ClearTable(table["NAME"].ToString());
281                }
282returntrue;
283            }
284catch285            {
286returnfalse;
287            }
288        }
289290///<summary>291///     Allows the user to easily clear all data from a specific table.
292///</summary>293///<param name="table">The name of the table to clear.</param>294///<returns>A boolean true or false to signify success or failure.</returns>295publicbool ClearTable(String table)
296        {
297try298            {
299                 ExecuteNonQuery(String.Format("delete from {0};", table));
300returntrue;
301            }
302catch303            {
304returnfalse;
305            }
306        }
307308///<summary>309///     Allows the user to easily reduce size of database.
310///</summary>311///<returns>A boolean true or false to signify success or failure.</returns>312publicbool CompactDB()
313        {
314try315            {
316                 ExecuteNonQuery("Vacuum;");
317returntrue;
318            }
319catch (Exception)
320            {
321returnfalse;
322            }
323        }
324    }
325 }
View Code

参考2:

关于如何正确使用System.Data.SQLite提高性能

SQLite .NET performance, how to speed up things?

You definitely need a transaction. If you don‘t, SQLite starts its own transaction for every insert command so you‘re effectively doing 86000 transactions as is.

It looks you‘re also opening and closing the connection each time, along with resetting the CommandText each time. This is unnecessary and doubtless slowing you down, it‘ll go much faster if you:

  • Open the connection once
  • Build the command once , adding the parameters to it once.
  • Start the transaction
  • Loop through, changing the parameter values only before calling ExecuteNonQuery
  • Commit the transaction.
  • Close the connection.

I think you could reduce your 20 minutes down to just a few seconds this way.

Edit: this is what I mean:

技术分享 技术分享 
                 1
                public
                void
                 InsertItems()

                 2
                {

                 3     SQLiteConnection connection  = new SQLiteConnection(SomeConnectionString);
 4     SQLiteCommand command = connection.CreateCommand();
 5     SQLiteTransaction transaction = connection.BeginTransaction();
 6 7     command.CommandText = "INSERT OR IGNORE INTO Result " 8 + "(RunTag, TopicId, DocumentNumber, Rank, Score) " +
 9"VALUES (@RunTag, @TopicId, @DocumentNumber, @Rank, @Score)";
1011     command.Parameters.AddWithValue("@RunTag", "");
12     command.Parameters.AddWithValue("@TopicId", "");
13     command.Parameters.AddWithValue("@DocumentNumber", "");
14     command.Parameters.AddWithValue("@Rank", "");
15     command.Parameters.AddWithValue("@Score", "");
1617foreach ( /* item to loop through and add to db */ )
18    {
19        InsertResultItem(runTag, topicId, documentNumber, rank, score, command);
20    }
2122    transaction.Commit();
23    command.Dispose();
24    connection.Dispose();
25}
2627publicint InsertResultItem(string runTag, int topicId, string documentNumber, int rank, double score, SQLiteCommand command)
28{
29     command.Parameters["@RunTag"].Value = runTag;
30     command.Parameters["@TopicId"].Value = topicId;
31     command.Parameters["@DocumentNumber"].Value = documentNumber;
32     command.Parameters["@Rank"].Value = rank;
33     command.Parameters["@Score"].Value = score;
34return command.ExecuteNonQuery();
35 }
View Code

It only uses one connection, one transaction and one command, so all you‘re changing is the parameter values each time. 

 

我自己实现的一个简易版本：

                 1
                using
                 System;

                 2
                using
                 System.Collections.Generic;

                 3
                using
                 System.Linq;

                 4
                using
                 System.Text;

                 5
                using
                 System.Threading.Tasks;

                 6
                using
                 System.Data.SQLite;

                 7
                 8
                namespace
                 Utility

                 9
                {

                10
                /*
                Multithread safety: No!
                */
                11
                public
                class
                 SQLiteDB

                12
                    {

                13
                private
                 SQLiteConnection    m_db_conn;

                14
                private
                 SQLiteTransaction    m_transaction;

                15
                private
                bool
                                m_is_transaction;

                16
                private
                 SQLiteCommand        m_transaction_cmd;

                17
                18
                public
                 SQLiteDB()

                19
                        {

                20             m_is_transaction = false;
21        }
2223public SQLiteDB(string db_path)
24        {
25             m_is_transaction = false;
26             m_db_conn = new SQLiteConnection(string.Format("Data Source={0}", db_path));
27            m_db_conn.Open();
28        }
29publicvoid Open(string db_path)
30        {
31             m_db_conn = new SQLiteConnection(string.Format("Data Source={0}", db_path));
32            m_db_conn.Open();
33        }
34publicvoid Close()
35        {
36if (m_db_conn.State != System.Data.ConnectionState.Closed)
37            {
38                m_db_conn.Close();
39                m_db_conn.Dispose();
40            }
41if (null != m_transaction_cmd)
42            {
43                m_transaction_cmd.Dispose();
44            }
45        }
4647publicvoid BeginTransaction()
48        {
49             m_is_transaction = true;
50             m_transaction_cmd = m_db_conn.CreateCommand();
51             m_transaction = m_db_conn.BeginTransaction();
52        }
5354publicvoid Commit()
55        {
56if (m_is_transaction)
57            {
58                m_transaction.Commit();
59                m_transaction_cmd.Dispose();
60                 m_is_transaction = false;
61            }
62        }
6364publicvoid Rollback()
65        {
66if (m_is_transaction)
67            {
68                m_transaction.Rollback();
69                m_transaction_cmd.Dispose();
70                 m_is_transaction = false;
71            }
72        }
7374publicint ExecuteNonQuery(string non_query_sql)
75        {
76if (!m_is_transaction)
77            {
78                 SQLiteCommand sql_cmd = new SQLiteCommand(m_db_conn);
79                 sql_cmd.CommandText = non_query_sql;
80return sql_cmd.ExecuteNonQuery();
81            }
82else83            {
84                 m_transaction_cmd.CommandText = non_query_sql;
85return m_transaction_cmd.ExecuteNonQuery();
86            }
87        }
88    }
89 }

 

原文：http://www.cnblogs.com/dearcarlos/p/4288136.html

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