HyperNetDatabase

M L Viñas Livschitz

4.11/5 (14 votes)

Mar 18, 2004

4 min read

125654

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HyperNetDatabase is a single process multithreading and blackout safe database

Sample Image - maximum width is 600 pixels

Introduction

This project was developed in order to help users that use databases like commercial ACCESS for small projects and then are subject to commercial laws. This is a simple solution for a database engine that can supply a good power to normal database tasks. This driver is free (GPL).

Using the code

Link the two DLLs HyperNetDatabase.DLL and NetFrmExts.DLL to your project and you'll be linked. Note use R2 Only, R1 is older and unstable.

To open a database and make a select:

using HyperNetDatabase.R2;
...
Database db = new Database();
db.Open("file.hnd"); // creates or opens database
...
..
DataTable result = db.Select(
    new string[]{"SEQNAME"}, // fields as an array of strings
    "$Sequences", // Name of the table
    new object[,]{ {"SEQNAME","=",myseq} } 
  // pairs of filter conditions : ... WHERE SEQNAME=myseq AND ...
    );
..
db.Close();

Public Static Methods

DataRow2NameAndValue Converts a DataRow in a NameAndValue object with skipRows.

Public Instance Constructors

Database Constructor

Default constructor

Public Instance Properties

`Filename`	Filename of the database
`Lock`	Global lock, used to lock other thread to make concurrent queries. Example: Read and then insert.
`State`	Connection state

Public Instance Methods

AddField Adds a field

AddFieldIfNotExist Adds a field if it not exists

AddTable Adds a table

AddTableIfNotExist Adds a table if it not exists

Close Closes a database

Delete

SQL DELETE query Example:

   using HyperNetDatabase.R2;
   ...
   Database db = new Database();
   db.Open("file.hnd"); 
    // creates or opens database
   ...
   string StockName = "peppers";
   DataTable result = db.Delete("Stock",
   new object[,]{ {"NAME","=",StockName} }
   );
   ...

Is the same as: DELETE Stock WHERE NAME=@StockName

WHERE expression: Is an C# expresion for making a where as a filter.

new object[,]{ {"{FIELDNAME}",{operand},{parameter}},... } Is the same as "field operand parameter AND ..."
null Means the same as no where condition.

Operand	Effect
=	Equality
>	Value of left field name is greater than right constant value variable
>=	Value of left field name is greater or equal than right constant value variable
<	Value of left field name is less than right constant value variable
<=	Value of left field name is less or equal than right constant value variable
!=	Value of left field name is different than right constant value variable

DropTable Removes a table

DropTableIfExists Drops a table if the table exists

Dump Dumps pages state

ExistsTable Returns true if the table exists

FlushIndexes Destroys in memory indexes. Do this if your were walking for many tables and you memory resources are low.

ForcedInsert

Overloaded. More known as Update or Insert (Sets values by a keyfield) Inserts if the condition does not match or updates if the condition matches.

   db.ForcedInsert( "Stock", "NAME", 
     "Peppers", "Qty", 0.5m );

Is the same as:

   SELECT Count(*) FROM STOCK WHERE NAME="Peppers";
   if count > 0 then
   UPDATE STOCK SET Qty=0.5 WHERE NAME="Peppers";
   else
   INSERT INTO STOCK (NAME,Qty) 
      VALUES ("Peppers",0.5);

ForcedSelect Obtains a value and if it not exists obtains it's default value

GetTableNames Gets all tables in this database

GetUserFields Fields for users

Insert

Inserts data into a Table Example:

   using HyperNetDatabase.R2;
   ...
   Database db = new Database();
   db.Open("file.hnd"); 
    // creates or opens database
   ...
   string StockName = "peppers";
   DataTable result = db.Insert(
    "Stock", new object[,]
  { {"NAME",StockName}, {"QTY",0.5m} } );
   ...

Is the same as: INSERT INTO Stock (NAME,QTY) VALUES (@StockName,0.5);

SET expression: Is an C# expresion for indicate a FIELD with its VALUE.new object[,]{ {"{FIELDNAME}",{parameter}},... } Is the same as "SET field = parameter, ..."Example 1:

     new object[,]{ {"QTY",0.5m} }

Example 2:

     new object[,]{ {"STRNAME","peppers"}, 
      {"QTY",0.5m} }

LogToFile (inherited from LogSupport) Saves a string in the log file

Open Open

PreloadIndexes Preloads indexes for table to make reads faster

Select

SQL Select query. Example:

   using HyperNetDatabase.R2;
   ...
   Database db = new Database();
   db.Open("file.hnd"); // creates or opens database
   ...
   string StockName = "peppers";
   DataTable result = db.Select(null,"Stock",
   new object[,]{ {"NAME","=",StockName} }
   );
   ...
   result = db.Select(new string[]{"NAME"},"Stock",
   new object[,]{ {"NAME","=",StockName} }
   );
   ...

Is the same as:

SELECT * FROM Stock WHERE NAME=@StockName
SELECT NAME FROM Stock WHERE NAME=@StockName

WHERE expression: Is an C# expresion for making a where as a filter.

new object[,]{ {"{FIELDNAME}", {operand},{parameter}},... } Is the same as "field operand parameter AND ..."
null Means the same as no where condition.

Operand	Effect
=	Equality
>	Value of left field name is greater than right constant value variable
>=	Value of left field name is greater or equal than right constant value variable
<	Value of left field name is less than right constant value variable
<=	Value of left field name is less or equal than right constant value variable
!=	Value of left field name is different than right constant value variable

seqCreate Overloaded. Creates a sequence.

seqCurrentValue Current sequence value

seqDrop Sequence drop

seqExists Sequence exists?

seqNextValue Next sequence value (and autoincrement)

Update

SQL UPDATE query Example:

   using HyperNetDatabase.R2;
   ...
   Database db = new Database();
   db.Open("file.hnd"); // creates or opens database
   ...
   string StockName = "peppers";
   DataTable result = db.Update("Stock",
   new object[,]{ {"NAME",StockName}, {"QTY",0.5m} },
   new object[,]{ {"NAME","=","pepperoni"} }
   );
   ...

Is the same as: UPDATE Stock SET NAME=@StockName, QTY=0.5 WHERE NAME=pepperoni

WHERE expression: Is an C# expresion for making a where as a filter.

new object[,]{ {"{FIELDNAME}",{operand},{parameter}},... } Is the same as "field operand parameter AND ..."
null Means the same as no where condition.

Operand	Effect
=	Equality
>	Value of left field name is greater than right constant value variable
>=	Value of left field name is greater or equal than right constant value variable
<	Value of left field name is less than right constant value variable
<=	Value of left field name is less or equal than right constant value variable
!=	Value of left field name is different than right constant value variable

SET expression: Is an C# expresion for indicate a FIELD with its VALUE.

new object[,]{ {"{FIELDNAME}",{parameter}},... } is the same as "SET field = parameter, ..."

Example 1:

     new object[,]{ {"QTY",0.5m} }

Example 2:

     new object[,]{ {"STRNAME","peppers"}, 
      {"QTY",0.5m} }

Points of Interest

Support all SQL basic functions.
Additional features.
Protect from Blackouts
Multithreading-safe

History

RELEASE VERSION 2.0.0 NOTES - 2004-03-17

Features:

First stable version
Support all SQL basic functions.
Additional features.
Protect from Blackouts
Multithreading-safe