Built-in Functions and Variables

How to use built-in functions and variables

java

package your.domain;

public interface PersonDao {
  void insertPerson( Person person );
}

xml

<mapper namespace="your.domain.PersonDao">

  <insert id="insertPerson">
        @var kv = ng.kv( ng_args[0], '', true, true );
        @var id = ng.id( ng_args[0] );
        @var tagName = ng.tagName( ng_args[0] );
        INSERT VERTEX `${ tagName }` (
            ${ ng.join( @kv.columns, ",", "ng.schemaFmt" ) }
        )
        VALUES ${ id } : (
            ${ ng.join( @kv.values ) }
        );
  </insert>

</mapper>

In this example, built-in functions such as ng.kv, ng.id, ng.tagName, ng.join, ng.schemaFmt, and the built-in parameter ng_args are used. After understanding the usage, we will further introduce the functions in the following content.

Built-in Variables

ng_cm ClassModel Dao interface class model, making it easier to get more class information in the xml (1.1.0-rc)
ng_mm MethodModel Dao interface method model, making it easier to get method information in the xml, including input parameter types. (1.1.0-rc)
ng_args The original parameters passed to the Dao interface, before serialization. (1.1.0-rc)

Built-in Functions

ng.valueFmt

Format data values of uncertain types, ignoring whether to append single quotes and date formatting, and directly pass the original java type

Parameter Position	Parameter Description	Type	Required	Default Value
1	Value	Object	Y
2	If it is a string, whether to append .* before and after to form a fuzzy query	boolean	N	false

Starting from v1.1.2, string types are escaped by default, which can be turned off using: ValueFmtFn.setEscape( false )

ng.schemaFmt

Add ` before and after the schema name to avoid conflicts with database keywords

Parameter Position	Parameter Description	Type	Required	Default Value
1	Schema name, such as tagName, edgeName, propertyName	Object	Y

ng.tagName

Used to get the tag name from the entity class or Dao interface

Parameter Position	Parameter Description	Type	Required	Default Value
1	Entity class object corresponding to the Schema	Object	Y
2	Class model, pass in using `ng_cm`	ClassModel	N	null

ng.pkField

Used to get the primary key attribute, java.lang.reflect.Field

Parameter Position	Parameter Description	Type	Required	Default Value
1	Entity class type	Class<?>	Y
2	If there is no primary key, whether to report an error and interrupt	Boolean	N	false

ng.pkName

Used to get the primary key name, String

Parameter Position	Parameter Description	Type	Required	Default Value
1	Entity class object	Object	Y
2	Use column name when true, use attribute name when false	Boolean	N	true

ng.entityType

Used to get the entity class type

Parameter Position	Parameter Description	Type	Required	Default Value
1	Entity class object	Object	Y

ng.fieldNames

Get the attribute name collection (excluding primary key)

Parameter Position	Parameter Description	Type	Required	Default Value
1	Entity class object	Object	Y
2	Use column name when true, use attribute name when false	Boolean	N	true

ng.id

Get the id value

Parameter Position	Parameter Description	Type	Required	Default Value
1	Entity class object	Object	Y
2	If there is no primary key, whether to report an error and interrupt	Boolean	N	true
3	If the value is empty, return a new value generated by the primary key generator when true, return null when false	Boolean	N	true

ng.kv

Get multiple collections through the entity object
columns Column name collection
valueNames Attribute name collection
values Value collection
types Attribute types

Parameter Position	Parameter Description	Type	Required	Default Value
1	Entity class object	Object	Y
2	Parameter name prefix	String	N	null
3	Exclude primary key	Boolean	N	true
4	Exclude null values	Boolean	N	true
5	If there is no primary key, whether to report an error and interrupt	Boolean	N	true

ng.join

Format the collection

Parameter Position	Parameter Description	Type	Required	Default Value
1	Collection to be formatted	Iterable	Y
2	Separator between elements	String	N	`,`
3	Function name, before each element is concatenated, it can be formatted by the specified formatting function and then concatenated	String	N	null

ng.ifStringLike

When the type is a string, prepend and append .*

Parameter Position	Parameter Description	Type	Required	Default Value
1	Value	Object	Y
2	Attribute type	Object	N	null
3	Attribute name, used to not write the value in plain text in ngql, but use the parameter name to let nebula take the value from the parameters	String	N	null

ng.include

Reference nGQL snippet

Parameter Position	Parameter Description	Type	Required	Default Value
1	The nGQL snippet ID to be referenced. To reference nGQL snippets from other mappers, add the namespace of the snippet before the snippet ID, e.g., your.domain.TestDao.nGQL-ID	String	Y
2	Additional parameters when referencing nGQL snippets, which will be used preferentially when generating statements	Object	N	null

Built-in Functions and Variables ​

How to use built-in functions and variables ​

Built-in Variables ​

Built-in Functions ​

Built-in Functions and Variables

How to use built-in functions and variables

Built-in Variables

Built-in Functions