Class: Json2sql::WhereModel

Inherits:
Object
  • Object
show all
Defined in:
lib/json2sql/where_model.rb

Overview

Builds a SQL WHERE clause from a Hash describing the conditions.

Input structure mirrors the JSON format used in the C++ backend:

{
  "and" => {
    "name"   => "john",           # implicit LIKE '%john%'
    "age"    => 30,               # implicit equality
    "status" => { "in" => [1,2] },
    "score"  => { ">=" => 4.5 },
    "col"    => { "null" => true },  # IS NULL / IS NOT NULL
    "ref"    => { "=" => "$.table.col" }  # column reference
  },
  "or" => { ... }
}

Supported operators: = < > <= >= != <>

in  !in  like  !like

String pseudo-actions: contains (LIKE %v%), first (LIKE v%), last (LIKE %v)

Instance Method Summary collapse

Constructor Details

#initialize(sql, table, relation) ⇒ WhereModel

Returns a new instance of WhereModel.



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# File 'lib/json2sql/where_model.rb', line 25

def initialize(sql, table, relation)

  @sql = sql

  @table = table.to_s

  @relation = relation
end

Instance Method Details

#build(params) ⇒ Object 



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# File 'lib/json2sql/where_model.rb', line 34

def build(params)

  has_relation  = @relation.kind != WhereRelation::NONE

  has_where_and = params["and"].is_a?(Hash)

  has_where_or  = params["or"].is_a?(Hash)

  return unless has_relation || has_where_and || has_where_or

  parts = []

  parts << with_buffer { @relation.build_table_relation(@sql, @table) } if has_relation

  scope = has_where_and ? " AND " : " OR "
  
  group = params["and"] || params["or"]

  if group

    frag = build_column_group(group, scope)

    parts << frag unless frag.empty?
  end

  return if parts.empty?

  @sql << " WHERE " << parts.join(" AND ")
end