Queries
BoxLang provides the easiest way to query a database
Last updated
Was this helpful?
BoxLang provides the easiest way to query a database
Last updated
Was this helpful?
CFML became famous in its infancy because it was easy to query databases with a simple cfquery tag and no verbose ceremonious coding. There is no ceremony, just a plain datasource definition in the administrator, and we could easily query the database.
In modern times, we obviously have many more ways to query the database. With BoxLang, defining data sources can occur not only , but also , not to mention defining datasources at runtime programmatically or .
A query is a request to a database representing the results' rows and columns. It returns a BoxLang query object containing a record set and other metadata information about the query. The query can ask for information from the database, write new data to the database, update existing information in the database, or delete records from the database. This can be done in several ways:
Using the bx:query tag. ()
Using the queryExecute() function. ()
Here's the tag syntax for a query using a named "pantry" datasource:
Most often you'll be writing queries in script syntax. Here's an example of using the in a script-syntax query:
The datasource configuration struct should be defined exactly the same whether you are using an inline, ad-hoc datasource or configuring a datasource in your boxlang.json or Application.bx. Make sure you have a "driver" key defined OR the driver clearly denoted in the JDBC url:
The query object can be iterated on like a normal collection through a for, bx:loop or bx:output , each() constructs.
You leverage the bx:output tag by passing the query to it. Then in the block of the tag you use dot/array notation and interpolation to output the column you want. BoxLang will iterate over all rows in the query for you.
Using Loops
As you can see, many ways to iterate over the query exist. Choose the approach that suits your needs.
BoxLang allows you to leverage the each() operations in a multi-threaded fashion. The queryEach() or each() functions allow for a parallel and maxThreads arguments so the iteration can happen concurrently on as many maxThreads as supported by your JVM.
This is incredibly awesome, as now your callback will be called concurrently! However, please note that once you enter concurrency land, you should shiver and tremble. Thread concurrency will be of the utmost importance, and you must ensure that var scoping is done correctly and that appropriate locking strategies are in place.
Even though this approach to multi-threaded looping is easy, it is not performant and/or flexible. Under the hood, the BoxLang uses a single thread executor for each execution, do not allow you to deal with exceptions, and if an exception occurs in an element processor, good luck; you will never know about it. This approach can be verbose and error-prone, but it's easy. You also don't control where the processing thread runs and are at the mercy of the engine.
If you would like a functional and much more flexible approach to multi-threaded or parallel programming, consider using the ColdBox Futures approach (usable in ANY framework or non-framework code). You can use it by installing ColdBox or WireBox into any BoxLang application and leveraging our async programming constructs, which behind the scenes, leverage the entire Java Concurrency and Completable Futures frameworks.
Here are some methods that will allow you to do parallel computations:
all( a1, a2, ... ):Future : This method accepts an infinite amount of future objects, closures, or an array of closures/futures to execute them in parallel. When you call on it, it will return a future that will retrieve an array of the results of all the operations.
allApply( items, fn, executor ):array : This function can accept an array of items or a struct of items of any type and apply a function to each of the items in parallel. The fn argument receives the appropriate item and must return a result. Consider this a parallel map() operation.
anyOf( a1, a2, ... ):Future : This method accepts an infinite amount of future objects, closures, or an array of closures/futures and will execute them in parallel. However, instead of returning all of the results in an array like all(), this method will return the future that executes the fastest! Race Baby!
withTimeout( timeout, timeUnit ) : Apply a timeout to all() or allApply() operations. The timeUnit can be days, hours, microseconds, milliseconds, minutes, nanoseconds, and seconds. The default is milliseconds.
You can use the :varname notation in your SQL construct to denote a variable placeholder or ? to denote a positional placeholder. The bx:queryparam tag or the inline sqltype construct will bind the value to a specific database type to avoid SQL injection and to further the database explain plan via types. The available SQL binding types are:
bigint
bit
char
blob
clob
nclob
date
decimal
double
float
idstamp
integer
longvarchar
longnvarchar
money
money4
nchar
nvarchar
numeric
real
refcursor
smallint
sqlxml
time
timestamp
tinyint
varchar
queryNew()
queryAddRow()
queryAddColumn()
queryColumnArray()
queryColumnCount()
queryColumnData()
queryColumnExists()
queryColumnList()
queryCurrentRow()
queryDeleteColumn()
queryDeleteRow()
queryEach()
queryEvery()
queryFilter()
queryGetCell()
queryGetResult()
queryGetRow()
queryMap()
queryRecordCount()
queryReduce()
queryRowData()
querySetCell()
querySlice()
querySome()
querySort()
quotedValueList()
valueList()
You can use a combination of the methods above to create your own queries:
Query a local database variable without going through your database is another great way to query an already queried query. Too many queries?
Please note that using a query of queries can be quite slow sometimes, not all the time. An alternative approach is to use modern queryFilter() operations to actually filter out the necessary data from a query or querySort(), etc.
You can also determine the return type of database queries as something other than the BoxLang query object. You can choose an array of structs or a struct of structs. This is fantastic for modern applications that rely on rich JavaScript frameworks and produce JSON.
Using qb, you can:
Quickly scaffold simple queries
Make complex, out-of-order queries possible
Abstract away differences between database engines
BoxLang supports the following query options:
result - Name of the variable to store the query results in.
maxRows - Limit the number of rows retrieved from the database.
queryTimeout - Max execution time to allow the query to run before aborting with a query timeout error.
returnType - Return the result as an array, query, or struct.
fetchSize - Set a custom result set batch size to improve performance on large queries. Is equivalent to blockfactor in CFML, but matches the JDBC statement option name.
cache - Enable or disable caching
cacheKey - A unique string used to identify this query for caching purposes.
cacheProvider - Name of the cache provider used for caching this query. A default cache provider will be assigned if none set,
cacheTimeout - Max time, as a duration, to allow cached results to be returned.
blockfactor - alias for fetchSize
cacheID - alias for cacheKey
cacheRegion - alias for cacheProvider
cachedAfter - coerced to a cacheTimeout duration if the current datetime is "after" the cachedAfter value.
cachedWithin - alias for cacheTimeout, unless value is "request". Support planned for cachedWithin=request.
The following options are unimplemented, but support is planned:
cachedWithin=request
timezone
psq
dbtype=query
lazy
The following query options are unimplemented, with no support planned:
username
password
debug
clientInfo
fetchClientInfo
ormoptions
For more information on datasource configuration, see our
We usually won't have the luxury of simple queries; we will need user input to construct our queries. Here is where you need to be extra careful not to allow for BoxLang has several ways to help you prevent SQL Injection, whether using tags or script calls. Leverage the bx:queryparam construct/tag () and always sanitize your input via the encode functions in BoxLang.
Please note that the cf_sql_{type} syntax is only supported when is installed. Hence, {type} should be preferred in all new queries moving forward.
Several query methods are available in BoxLang that can help you manage queries and create them on the fly (). Please note that you can also use chaining and member functions as well.
This is achieved by passing the returntype attribute within the query options or just an attribute of the bx:query tag ()
We have created a fantastic module to deal with queries in a fluent and elegant manner. We call it QB short for query builder (). You can install it using CommandBox into your application by just saying:
You can find all the documentation in our Ortus Books docs:
For CFML compatibility, the following options are also supported once is installed:
