Class SessionExtensions

Extends ISession with useful methods.

Inheritance

object

SessionExtensions

Namespace: Neon.Cassandra

Assembly: Neon.Cassandra.dll

Syntax

public static class SessionExtensions

Methods

ExecuteAsync(ISession, string)

Executes a text command asynchronously.

Declaration

public static Task<RowSet> ExecuteAsync(this ISession session, string cqlText)

Parameters

Type	Name	Description
ISession	session	The database session.
string	cqlText	The command or query text.

Returns

Type	Description
Task<RowSet>	The resulting RowSet.

ExecuteBatch(ISession, string)

Executes a batch of SQL commands saeparated by lines including go separators. This works like Microsoft SQL server related tools.

note

The term batch here is different from the usual Cassandra terminology, where batch refers an BatchStatement which may include multiple statements that are executed together atomically. Batch here refers to statements extracted from the text passed and then executed individually.

Sorry for the confusion here, but we used this to be consistent with the our Postgres extensions and frankly, we couldn't think of a better term.

Declaration

public static void ExecuteBatch(this ISession session, string batchText)

Parameters

Type	Name	Description
ISession	session	The database session.
string	batchText	The SQL commands possibly separated by go lines.

Remarks

It's often necessary to execute a sequence of SQL commands that depend on each other. One example is a command that creates a table followed by commands that write rows. You might think that you could achieve this by executing the following as one command:

CREATE TABLE my_table (name text);
INSERT INTO my_table (name) values ('Jack');
INSERT INTO my_table (name) values ('Jill');

but this won't actually work because the database generates a query plan for the entire command and when it does this and sees the inserts into [my_table] but the table doesn't actually exist at the time the query plan is being created. So the command will fail.

What you really need to do is create the table first as a separate command and then do the inserts as one or more subsequent commands. This is not terribly convenient so we've introduced the concept of a batch of commands via this method. Here's what this would look like:

CREATE TABLE my_table (name text);
go
INSERT INTO my_table (name) values ('Jack');
INSERT INTO my_table (name) values ('Jill');

See how the go line separates the table creation from the inserts. This method will split the batchText into separate commands on any go lines and then execute these commands in order.

note

go is case insensitive and any leading or trailing space on the line will be ignored.

ExecuteBatchAsync(ISession, string)

Asynchronously a batch of SQL commands saeparated by lines including go separators. This works like Microsoft SQL server related tools.

note

The term batch here is different from the usual Cassandra terminology, where batch refers an BatchStatement which may include multiple statements that are executed together atomically. Batch here refers to statements extracted from the text passed and then executed individually.

Sorry for the confusion here, but we used this to be consistent with the our Postgres extensions and frankly, we couldn't think of a better term.

Declaration

public static Task ExecuteBatchAsync(this ISession session, string batchText)

Parameters

Type	Name	Description
ISession	session	The database session.
string	batchText	The SQL commands possibly separated by go lines.

Returns

Type	Description
Task	The tracking Task.

Remarks

note

This method doesn't actually execute the statements asynchronously because the Cassandra driver doesn't include an ISession.ExecuteAsync(string) method. This method simply calls ExecuteBatch(ISession, string). We're retaining this method for compatibility with our Postgres extensions.

It's often necessary to execute a sequence of SQL commands that depend on each other. One example is a command that creates a table followed by commands that write rows. You might think that you could achieve this by executing the following as one command:

CREATE TABLE my_table (name text);
INSERT INTO my_table (name) values ('Jack');
INSERT INTO my_table (name) values ('Jill');

but this won't actually work because the database generates a query plan for the entire command and when it does this and sees the inserts into [my_table] but the table doesn't actually exist at the time the query plan is being created. So the command will fail.

What you really need to do is create the table first as a separate command and then do the inserts as one or more subsequent commands. This is not terribly convenient so we've introduced the concept of a batch of commands via this method. Here's what this would look like:

CREATE TABLE my_table (name text);
go
INSERT INTO my_table (name) values ('Jack');
INSERT INTO my_table (name) values ('Jill');

See how the go line separates the table creation from the inserts. This method will split the batchText into separate commands on any go lines and then execute these commands in order.

note

go is case insensitive and any leading or trailing space on the line will be ignored.