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A database collector reads data from a Datasource. It holds the SQL that will be sent to the datasource to retrieve data.

The query columns must match up to any streams saving the data.

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Database Collector Properties

Basic Settings

FieldDescription
NameEnter the name of the database collector.
DatasourceSelect the datasource that this database collector will collect from.
Statement Expression

Enter an SQL query string, which can include PhixFlow Expressions. The database collector processes the query to retrieve data from the database; see  Statement Expressions, below, for details.

Allow Non-Scheduled Collection

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 to allow this database collector to be run as part of any ad-hoc analysis run that requires this data.

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 to restrict this database collector to being run as part of a scheduled Task Plan.

EnabledTick when the configuration is complete and the database collector is ready to be used.

Advanced

FieldDescription
TimeoutSpecify a time period in seconds, after which a query will timeout.
Datasource Instance Expression

The datasource to which this database collector is connected may list multiple database instances from which the data may be read. Each Datasource Instance is identified by a unique string. The database collector needs to know which specific datasource instance to use.

Enter an expression that evaluates to a plain text string that corresponds to one of the unique datasource instances.

If this expression is blank then the database collector assumes that there is only one instance to use. If there is more than one instance the database collector will be unable to determine which instance to use and PhixFlow will report an error.

Log Traffic

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  • Log Database Collector Statements: when ticked, PhixFlow always logs details of data loaded by database collectors, whatever is set here.

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Statement Expressions

Testing Expressions 
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When the database collector is enabled, the properties menu at has an option  Run Query and See Result. If you cannot see the option, click on

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 to expand the full menu. 

Use  Run Query and See Result to test the SQL query string in the expression. PhixFlow runs the SQL and opens a table showing the first page of returned data. You can  Run Query even if the database collector has not been saved.

Query Strings 
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The query string must return data in fields with the same name as the stream attributes you wish to populate. So to collect data into a stream with attributes account_number, cust_ref and eventsource from a table with fields account_number, customer_ref and eventsource, use the query string:

Code Block
select account_number, customer_ref as cust_ref, eventsource from billing_products where from_dat >= to_date({_fromDate}, 'yyyymmdd') and to_dat <= to_date({_toDate}, 'yyyymmdd')

Notice that the query string directly includes PhixFlow Expressions that calculate values.

Expressions must be

enclosed in curly brackets, starting with a { and ending with } 

take the form of a standard PhixFlow Expression. Expressions can include PhixFlow's Internal Variables. In the example above, {_fromDate} and {_toDate} are expressions that use internal variables to reference the stream period.

If the dates include a time element, use the query string:

Code Block
select account_number, customer_ref as cust_ref, eventsource from billing_products where from_dat >= to_date({_fromDate}, 'yyyymmdd.hh24miss') and to_dat <= to_date({_toDate}, 'yyyymmdd.hh24miss')


Note

Do not include the standard sqlplus terminator.  (For example, in Oracle, the terminator is a semi-colon).

Complex Replacement Expressions

You can use more complex PhixFlow expressions in queries where necessary. To do this, precede the expression (inside curly braces) with an = sign. For example

Code Block
select account_number, customer_ref from account{=accBlockString(_out.BlockID)}

There are some disadvantages when using = to precede an expression, as noted below, and therefore you should only use this when really necessary. For example, where the table or column names can vary, and are controlled by input data to the query - as in the above example, where part of the name of the table being queried is returned by a Macro "accBlockString", based on an input value "_out.BlockID".

Note: when you use the = sign to precede an expression, this may result in slower performance. If you are using this to apply a data transformation within the query, it is better to apply this transformation to the input data before you pass it into the query. This is because without the = sign PhixFlow can make use of more efficient query techniques (such as using bind variables) to optimise performance of the queries.

Note: when you use the = sign to precede an expression, PhixFlow does not automatically map PhixFlow types to database types. This means, for example, that if you pass a String PhixFlow type into a query without = you need only

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{_out.CustName}

but with = you need to format the string in the query as required by the syntax of the source database, for example

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{="'" + _out.CustName + "'"}

Similarly dates in expressions preceded by = must be formatted as required by the syntax of the source database.

Merging Directly from a Database Collector

If you are collecting data directly into a merge, your query must match the ordering represented by the grouping in the input pipe from the collector into the merge. For example, if you have specified Customer and Product as the grouping attributes on the pipe connecting the collector to the stream then you must include the appropriate order by expression in the SQL to ensure the data is sorted by customer and then product.

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Generate a Stream from a Query

From the hover menu from a database collector on a Using the Model Window, clicking  creates a new Stream with the attributes implied by the query. If the Datasource Instance Expression has been entered then the expression will be used to select the datasource, otherwise the first Datasource Instance alphabetically will be used. The new Stream will be shown on the model, connected to this Database Collector.

To use this feature, the supplied query must be pure SQL i.e. should not contain embedded expressions (as described above).

PhixFlow wraps the query with a "where 1= 0" to avoid a long running statement.

Time Data

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PhixFlow recognises date and date-time formats, but does not recognise time-only formats, for example HH:mm:ss. When a database collector loads time data, it applies the string data-type. This applies to data from MariaDB and SQL Server databases as there is no TIME data-type in Oracle DB.