6. Commands

HTSQL query may contain a list of commands, building a command chain. Each command in a chain gets results of previous command as an input and passes the output to the next one.

There are two types of commands:

• producers
• renderers

Chain of commands looks as:

producer [ producer ]... renderer

This way chain consists of one or more producer command and only one renderer at the end of chain. In the following reference each command is marked with it’s type.

There’s a special subtype of producer: query processors. If HTSQL query has a path_clause, query processor tells how to handle this clause. That’s why queries with path_clause must contain one and only one query processor at very start of the command chain. In this case command chin will look as:

query-processor [ producer ]... renderer

Note: HTSQL has defined default query processor and default renderer commands. If not overridden, query processor default to select() and renderer defaults to html().

• 6.1. Descriptor Commands
  • 6.1.1. version
  • 6.1.2. meta
  • 6.1.3. describe
  • 6.1.4. sql
  • 6.1.5. root
• 6.2. Query Processor Commands
  • 6.2.1. select
  • 6.2.2. insert
  • 6.2.3. update
  • 6.2.4. delete
  • 6.2.5. merge
• 6.3. Transformer Commands
  • 6.3.1. flatten
  • 6.3.2. interweave
  • 6.3.3. first
  • 6.3.4. pivot
  • 6.3.5. foreach
• 6.4. Formatter Commands
  • 6.4.1. txt
  • 6.4.2. csv
  • 6.4.3. tsv
  • 6.4.4. html
  • 6.4.5. xml
  • 6.4.6. yaml
  • 6.4.7. json
  • 6.4.8. jsonp
• 6.5. Transactions Supporting Command
  • 6.5.1. transaction