Posts Tagged ‘query’
SubSonic Tutorial ( Learn basics )
Following code uses version 2.2 and Northwind database as an example to illustrate the basics. You can use Linq queries also which is introduced from 2.1 pakala release. The same tutorial is in the following two files in case it is hard to read the following tutorial.
Insert the Record
//Fill the object to save. Please make sure that you fill all must (not null) object
Supplier sup = new Supplier();
sup.Address = "Test Address";
sup.City = "Ahmedabad";
sup.CompanyName = "IntelliPro";
sup.ContactName = "Test Contact";
sup.ContactTitle = "Manager";
sup.Country = "India";
sup.Fax = "01234567";
sup.HomePage = "http://www.xyz.com";
sup.Phone = "01293202";
sup.PostalCode = "380051";
sup.Region = "Test Region";
// call save
sup.Save();
Update the Record
//Fetch the object which is required to save. 30 is id of record
Supplier sup = new Supplier(30);
// Fill the property which needs to be saved.
sup.PostalCode = "380052";
sup.Region = "TestRegion2";
// call save
sup.Save();
Delete the Record
//If there are IsDelete flag then this function make true in this column. Else it delete the record from the database.
Supplier.Delete(30);
//In case you have IsDelete flag and you want to delete the function, use following code.
Supplier.Destroy(30);
Select all Record
// You can select all the record 2 ways.
// First using supplier object
SupplierCollection colSup = new SupplierCollection();
colSup.LoadAndCloseReader(Supplier.FetchAll());
// now colSup has all the record
// Second is just us collection’s Load method
SupplierCollection colSup = new SupplierCollection();
colSup.Load();
Select record by primary key
// 30 is primary key and in new object just pass it to the constructor
Supplier sup = new Supplier(30);
// if object successfully fetched from the database then following property will be true. So you can check to verify the record sometime whether record is loaded or not.
sup.IsLoaded
Select record by parameter other than primary key (but only one parameter)
SupplierCollection colSup = new SupplierCollection();
// It defaults to equal operation in FetchByParameter function
colSup.LoadAndCloseReader(Supplier.FetchByParameter (Supplier.Columns.Country,"India") );
// IF you want to use another comparision operator, you can use
colSup.LoadAndCloseReader(Supplier.FetchByParameter (Supplier.Columns.Country, SubSonic.Comparison.NotEquals,"India") );
// You can also apply order by at the end. To generate order by, you must use its static function Asc or Desc
// e.g. OrderBy.Asc or OrderBy.Desc and supply column name into the same.
colSup.LoadAndCloseReader(Supplier.FetchByParameter (Supplier.Columns.Country, SubSonic.Comparison.NotEquals,"India", OrderBy.Asc(Supplier.Columns.City) ) );
Following are the list of comparisions which we can use into comparing the parameter.
public enum Comparison
{
Equals = 0,
NotEquals = 1,
Like = 2,
NotLike = 3,
GreaterThan = 4,
GreaterOrEquals = 5,
LessThan = 6,
LessOrEquals = 7,
Blank = 8,
Is = 9,
IsNot = 10,
In = 11,
NotIn = 12,
OpenParentheses = 13,
CloseParentheses = 14,
BetweenAnd = 15,
}
Select record by parameter other than primary key (but more than one parameter)
// There are two methods for doing this. You can use any.
// First one is following
SupplierCollection colSup = new SupplierCollection();
colSup.Where(Supplier.Columns.City,"Ahmedabad");
colSup.Where(Supplier.Columns.CompanyName, Comparison.Like ,"Intelli");
// you can also use order by before calling Load function to order the result.
colSup.OrderByAsc(Supplier.Columns.PostalCode);
// Following statement load the records with above condition. Here one thing to note that
// It only uses where and that also with AND default. you cannot do OR here. For that
// you need to use second option
colSup.Load();
// Here is second method for doing the similar kind of thing
// Here you need to pass tablename or schema in the query.
// If Tables structure is available then you can pass Tables.Supplier else you can pass
// TableName.schema object
Query qry = new Query(Supplier.Schema);
// Query has many function and you can use multiple function for your query
qry.AddWhere(Supplier.Columns.City,"Ahmedabad");
qry.OR(Supplier.Columns.CompanyName, Comparison.Like ,"Intelli");
qry.OrderBy = OrderBy.Asc(Supplier.Columns.City);
SupplierCollection colSup = new SupplierCollection();
// It defaults to equal operation in FetchByParameter function
colSup.LoadAndCloseReader(qry.ExecuteReader());
Other Methods of the Query Objects
// Set order by. Its property. You can use order_by function as well.
qry.OrderBy
// Make In and Non In query
qry.IN
qry.NOT_IN
// And and OR condition
qry.AND
qry.OR
// Where condition
qry.AddWhere
// Find record between values
qry.AddBetweenValues
// Find record between dates
qry.AddBetweenAnd
You have other methods of query to execute other than execute reader.
You can use, Execute for update query, ExecuteDataSet for getting dataset and ExecuteScaler for scalar values.
Select from more than one table
There is no method available in 2.0.3 for the join. So we will use only View right now. But there are other method in latest version of subsonic for directly making Joins.
Suppose you wanted Invoices from the 5 tables joined, you can create the view Invoice and then you can use that object same way like tables and also you can query view to filter the data like tables.
Calling Stored Procedures
When you generate classes, the class is generated automatically for each stored procedure and views. For stored procedure SPs class is generated and all stored procedures are as static function so you can directly call without creating object as I have done below. You can find stored procedure in Northwind database.
StoredProcedure spSales = SPs.SalesByCategory("Test","2009");
DataSet ds = spSales.GetDataSet();
// Generally we use object’s collection to take the result in. So we can create one view like
// SalesByCategoryResult and take this result into it by calling funcitons like that
SalesByCategoryResultCollection colSup = new SalesByCategoryResultCollection();
colSup.LoadAndCloseReader(spSales.GetReader());
Customized Query (Which do not fit in any of above point)
There are two ways. Either you can make stored procedure and generate the SP function and use it or you can make the query as below.
// Make sql statement. But make sure that you do not hardcode any values. Below query can be made with subsonic
// but it is used just only for example.
string query = "SELECT * FROM " + Supplier.Schema.TableName + " WHERE " + Supplier.Columns.Address + " LIKE %abc%";
// Now create querycommand object with above query
QueryCommand qc = new QueryCommand(query);
// DataService class is used to run query command object. QueryCommand object is generally used for
// making parameterized queries which might not be fitted using query object. And you can take those
// Values in Collection
SupplierCollection colSup = new SupplierCollection();
colSup.LoadAndCloseReader(DataService.GetReader(qc));
Aggregate Functions
If you want to use aggregate function on some table, you can use it following way.
Query qry = new Query(Supplier.Schema);
// following returns Maximum supplierid in the table
int SupplierId = qry.GetMax(Supplier.Columns.SupplierID);
//There are other functions available for aggregate in query
qry.GetAverage
qry.GetCount
qry.GetMin
qry.GetSum
How to query different type database object like table, view, trigger using sysobject
following is the query for selecting all object from all database
SELECT name, id, xtype, uid, info, status, base_schema_ver, replinfo, parent_obj, crdate, ftcatid, schema_ver, stats_schema_ver, type, userstat, sysstat, indexdel, refdate,version, deltrig, instrig, updtrig, seltrig, category, cache
FROM sys.sysobjects
|
There are various parameter which you can use as where to specify criteria.
If you want to search certain object type then
XTYPE =
‘U’ | For table |
‘PK’ | For Primary Keys |
‘F’ | For Foreight Keys |
‘V’ | For views |
‘P’ | For stored procedures |
‘TR’ | For triggers |
‘S’ | For system objects |
‘FN’ | Function |
You can also add like query on name to give specific resultset.