This small class (SQLiteHelper.cs) is built on top of System.Data.SQLite.DLL. A reference of this DLL must be added into your projects.

​

List of Simplified Functions

  2. GetTableStatus
  3. GetTableList
  4. GetColumnStatus
  5. CreateTable
  6. UpdateTableStructure
  7. BeginTransaction, Commit, Rollback
  8. Select
  9. Execute
  10. ExecuteScalar
  11. Escape
  12. Insert
  13. Update
  14. LastInsertRowId
  15. RenameTable
  16. CopyAllData
  17. DropTable
  18. ShowDatabase
  19. AttachDatabase, DetachDatabase

Getting Start

Add this using statement at the top of your class:


​ 

using System.Data.SQLite;


​​SQLiteConnection​​ and ​​SQLiteCommand​​ have to be initialized before using ​​SQLiteHelper​​:

Example:

​ 

using (SQLiteConnection conn = new SQLiteConnection("data source=C:\\data"))
{
    using (SQLiteCommand cmd = new SQLiteCommand())
    {
        cmd.Connection = conn;
        conn.Open();

        SQLiteHelper sh = new SQLiteHelper(cmd);

        // do something...

        conn.Close();
    }
}


1. GetTableStatus

Get all information of tables in the database.

​ 

DataTable dt = sh.GetTableStatus();


Sample result:

type

name

tbl_name

rootpage

sql

table

sqlite_sequence

sqlite_sequence

3

CREATE TABLE sqlite_sequence(name,seq)

table

person2

person2

5

CREATE TABLE "person2"(

id integer primary key autoincrement,

name text,

tel text,

email text,

job text,

remarks text)

table

player

player

4

CREATE TABLE `player`(

id integer primary key autoincrement,

lvl integer,

weaponid integer,

teamid integer,

location text,

team_name text,

remarks text)

table

product

product

6

CREATE TABLE "product"(

id integer primary key autoincrement,

name text,

qty integer)

2. GetTableList

Get a list of tables in database.


​ 

DataTable dt = sh.GetTableList();


3. GetColumnStatus

Get all information of columns in specific table.


​ 

// Get column's information from table "person"
DataTable dt = sh.GetColumnStatus("person");


Sample Result:

cid

name

type

notnull

dflt_value

pk

0

id

integer

0

 

1

1

lvl

integer

0

 

0

2

weaponid

integer

0

 

0

3

teamid

integer

0

 

0

4

location

text

0

 

0

5

team_name

text

0

 

0

6

remarks

text

0

 

0

4. CreateTable

Create table.

Example table structure: Person

Column Name

Data Type

Primary Key

Auto Increment

Not Null

Default Value

id

int

true

true

 

 

name

text

 

 

 

 

membershipid

int

 

 

 

 

level

decimal

 

 

 

5.5


​ 

SQLiteTable tb = new SQLiteTable("person");

tb.Columns.Add(new SQLiteColumn("id", true));
tb.Columns.Add(new SQLiteColumn("name"));
tb.Columns.Add(new SQLiteColumn("membershipid", ColType.Integer));
tb.Columns.Add(new SQLiteColumn("level", ColType.Decimal, false, false, "5.5"));

sh.CreateTable(tb);


5. UpdateTableStructure

As the name said, it is used to update a table's structure. Maybe you have added new columns, or drop/deleted some columns. This method helps you to update it.

The process at code behind:

  • Assume that the old table is named: person
  • The class creates a temporary table (named: person_temp) with your new defined structure.
  • Copy all rows from person to person_temp.
  • Drop/delete table of person.
  • Rename table of person_temp to person

Code example:


​ 

SQLiteTable tb = new SQLiteTable();
tb.Columns.Add(new SQLiteColumn("id", true));
tb.Columns.Add(new SQLiteColumn("name"));
tb.Columns.Add(new SQLiteColumn("sku"));
tb.Columns.Add(new SQLiteColumn("code"));
tb.Columns.Add(new SQLiteColumn("category"));
tb.Columns.Add(new SQLiteColumn("remarks"));

sh.UpdateTableStructure("person", tb);


6. BeginTransaction, Commit, Rollback

What is transaction?

By default, every SQL query that is sent to SQLite database engine happens in a transaction. The engine automatically BEGIN a transaction and COMMIT it at the end. COMMIT is something like "Make it take effect".

If we send 3 SQL queries (INSERT, UPDATE, DELETE, etc...), 3 transactions are taken place. According to"...A transaction normally requires two complete rotations of the disk platter, which on a 7200RPM disk drive limits you to about 60 transactions per second..."

Which means, with a 7200RPM hard disk, the best that we can do is 60 INSERTs (or UPDATE, DELETE, etc) per second.

But, If we manually issue a BEGIN TRANSACTION, all the queries will be wrapped in single transaction, then SQLite can execute huge amount of queries per second. Somebody said he can execute 10 million per second at [​​stackoverflow.com​​], but this is also depends on the speed of hard disk that you are using.

Code example with SQLiteHelper:

​ 

sh.BeginTransaction();

try
{
    // INSERT.....
    // INSERT.....
    // UPDATE....
    // ... skip for another 50,000 queries....
    // DELETE....
    // UPDATE...
    // INSERT.....

    sh.Commit();
}
catch
{
    sh.Rollback();
}


ROLLBACK, in the above example means Cancel Transaction. All queries that have sent to SQLite database within that specific transaction are dismissed.

7. Select

Return the query result in DataTable format.

  • ​​Select(string sql)​​
  • ​​Select(string sql, Dictionary<string, object> dicParameters = null)​​
  • ​​Select(string sql, IEnumerable<SQLiteParameter> parameters = null)​​

Example 1:


​ 

DataTable dt = sh.Select("select * from person order by id;");


Example 2 (With parameters support):

​ 

var dic = new Dictionarystring, object();
dic["@aaa"] = 1;
dic["@bbb"] = 1;
DataTable dt = sh.Select("select * from member where membershipid = @aaa and locationid = @bbb;", dic);


Example 3 (With parameters support):

​ 

DataTable dt = sh.Select("select * from member where membershipid = @aaa and locationid = @bbb;",
    new SQLiteParameter[] { 
        new SQLiteParameter("@aaa", 1),
        new SQLiteParameter("@bbb", 1)
    });


8. Execute

Execute single SQL query.

  • ​​Execute(string sql)​​
  • ​​Execute(string sql, Dictionary<string, object> dicParameters = null)​​
  • ​​Execute(string sql, IEnumerable<SQLiteParameter> parameters = null)​​

Example:

​ 

sh.Execute("insert into person(name)values('hello');");


9. ExecuteScalar

Return the result of first row first column in specific data type.

  • ​​ExecuteScalar(string sql)​​
  • ​​ExecuteScalar(string sql, Dictionary<string, object> dicParameters = null)​​
  • ​​ExecuteScalar(string sql, IEnumerable<SQLiteParameter> parameters = null)​​
  • ​​ExecuteScalar<datatype>(string sql)​​
  • ​​ExecuteScalar<datatype>(string sql, Dictionary<string, object> dicParameters = null)​​
  • ​​ExecuteScalar<datatype>(string sql, IEnumerable<SQLiteParameter> parameters = null)​​

Example:


​​​​​ 

string a = sh.ExecuteScalar<string>("select 'Hello!';");

int b = sh.ExecuteScalar<int>("select 1000;");

decimal c = sh.ExecuteScalar<decimal>("select 4.4;");

DateTime d = sh.ExecuteScalar<DateTime>("select date('now');");

byte[] e = sh.ExecuteScalar<byte[]>("select randomblob(16);");


10. Escape

Escape string sequence for text value to avoid SQL injection or invalid SQL syntax to be constructed.


​ 

sh.Execute("insert into person(name) values('" + Escape(input) + "');");


11. Insert

Insert new row of data. All data will be added as parameters at code behind. This support blob (byte[]) value too.

​ 

var dic = new Dictionary<string, object>();
dic["name"] = "John";
dic["membershipid"] = 1;
dic["level"] = 6.8;

sh.Insert("person", dic);


12. Update

Update row. All data will be added as parameters at code behind. This support blob (byte[]) value too.

Example 1: Update with single condition (where id = 1)

​ 

var dicData = new Dictionary<string, object>();
dicData["name"] = "no name";
dicData["membershipid"] = 0;
dicData["level"] = 5.5;

sh.Update("person", dicData, "id", 1);


Example 2: Update with multiple condition (where membership = 1 and level = 5.5 and teamid = 1)


​ 

var dicData = new Dictionary<string, object>();
dicData["name"] = "no name";
dicData["status"] = 0;
dicData["money"] = 100;
dicData["dateregister"] = DateTime.MinValue;

var dicCondition = new Dictionary<string, object>();
dicCondition["membershipid"] = 1;
dicCondition["level"] = 5.5;
dicCondition["teamid"] = 1;

sh.Update("person", dicData, dicCondition);


13. LastInsertRowId

Get the last issued id (Auto-Increment)

​ 

sh.Insert("person", dicData);
long id = sh.LastInsertRowId();


14. RenameTable

Rename a table.

​ 

sh.RenameTable("person", "person_backup");


15. CopyAllData

Copy all data from one table to another.

​ 

sh.CopyAllData("person", "person_new");


Before copying, ​​SQLiteHelper​​ will scan the two tables for match columns. Only columns that exist in both tables will be copied.

16. DropTable

Drop table, delete a table


​ 

sh.DropTable("person");


17. ShowDatabase

Display attached databases.


​ 

DataTable dt = sh.ShowDatabase();


18. AttachDatabase, DetachDatabase

Attach or detach a database


​ 

sh.AttachDatabase("C:\\data2013.sq3", "lastyeardb");
sb.DetachDatabase("lastyeardb");


That's it, guys/girls. Comments are welcome.