Oracle Database - JSON and the In-Memory Database

Marco Gralike
Principal Consultant
eProseed, The Netherlands
Oracle 20+ years experience
Oracle ACE Director
OakTable Member
www.xmldb.nl

 Many thanks for their endless patience (despite my stupid
questions and mistakes) and for helping out:
 Mark Drake (JSON / XMLDB)
 Beda Hammerschmidt (JSON/XMLDB)
 Andy Rivenes (DBIM)
 Maria Colgan (DB General / DBIM)

 What is JSON?
 Oracle 12.1.0.2
 Load & Store
 Select
 Index
 Oracle 12.2.0.1
 Generate
 Automate
 Improve performance via DBIM

Basic constructs
(recursive)
 Base values
number, string,
boolean, …
 Objects { }
sets of label-value
pairs
 Arrays [ ]
lists of values

 JSON data can also be
 Partitioned
 Used with Flashback
 Recovered (when proper backup)
 Used with Securefile storage
▪ Encryption
▪ Deduplication
▪ Compressed
 Multiple index options
 Caching advantages, etc., etc.,…

 New in Oracle Database 12.1.0.2.0
 Store and manage JSON documents in Database
▪ JSON documents stored as text
▪ JSON documents can be indexed
 Access JSON documents via developer-friendly ‘Document-Store’ API’s
 SQL query capabilities over JSON documents for reporting and analysis

 Allows Oracle RDBMS to be used as a JSON Document Store
 Enables storing, indexing and querying of JSON documents
 No new JSON data type
 IS JSON constraint used to ensure a column contains valid JSON
documents
 Apply to (N)CLOB, (N)VARCHAR2, RAW and BLOB data
 Enables use of .dotted notation to navigate JSON document structure and
access content

filelist.dat
./data/www.json-generator.com.01.json
sqlldr.sh
sqlldr userid=json/json control=sqlldr.ctl log=sqlldr.log bad=sqlldr.bad

sqlldr.ctl
LOAD DATA
INFILE 'filelist.dat'
truncate
INTO table JSON_DATA
FIELDSTERMINATED BY ',‘
( clob_filename filler char(120)
, clob_content LOBFILE(clob_filename) TERMINATED BY EOF
, nclob_filename filler char(120)
, nclob_content LOBFILE(nclob_filename)TERMINATED BY EOF
, bfile_filename filler char(120)
, bfile_content BFILE(CONSTANT "JSON_LOAD", bfile_filename))

 Check constraint guarantees that values are valid JSON
documents
 IS [NOT] JSON predicate
 ReturnsTRUE if column value is JSON, FALSE otherwise
 Full parse of the data while validating syntax
 Tolerant and strict modes
 Use to ensure that the documents stored in a column are valid
JSON

 LAX
 Default
 STRICT
 Among others:
▪ JSON property (key) name and each string value must be enclosed
in double quotation marks (")
▪ Fractional numerals must have leading zero ( 0.14 | .14)
▪ XML DB Developers Guide or JSON Standards (ECMA-404 / 262)
 More performance intensive than Lax

create table J_PURCHASEORDER
( ID RAW(16) NOT NULL,
DATE_LOADED TIMESTAMP(6) WITHTIME ZONE,
PO_DOCUMENT CLOB
CHECK (PO_DOCUMENT IS JSON) )
insert into J_PURCHASEORDER values(‘0x1’,‘{Invalid JSONText}');
ERROR at line 1:
ORA-02290: check constraint (DEMO.IS_VALID_JSON) violated

 ALL_JSON_COLUMNS
 DBA_JSON_COLUMNS
 USER_JSON_COLUMNS
 Will not show up when
 Check constraint combines condition IS JSON with another condition
using logical condition OR
 “jcol is json OR length(jcol) < 1000” ???

-- Default (lax)
SQL> SELECT json_column
2 FROM t
3 WHERE ( json_column IS JSON);
-- Explicit
SQL> SELECT json_column
2 FROM t
3 WHERE ( json_column IS JSON (STRICT));

SQL> insert into J_PURCHASEORDER
2 select SYS_GUID(),
3 SYSTIMESTAMP,
4 JSON_DOCUMENT
5 from STAGING_TABLE
6 where JSON_DOCUMENT IS JSON;
SQL> delete from STAGING_TABLE
2 where DOCUMENT IS NOT JSON;

 JSON content is accessible from SQL via
new operators
 JSON operators use JSON Path
language to navigate JSON objects
 Proposed extention to SQL standards

 The JSON Path language makes it possible to address the
contents of a JSON document
 A JSON path expression can address 1 of 4 items
▪ The entire object, a scalar value, an array, a specific object
 JSON Path expressions are similar to XPath Expressions
▪ The entire document is referenced by $
▪ All JSON path expressions start with a $ symbol
▪ Key names are separated by a ’.’ (period)
 JSON Path expressions are case sensitive

JSON Path Expression Type Contents
$.Reference String "ABULL-20120421"
$.ShippingInstructions.Address.zipcode Number 99236
$.ShippingInstructions.Address Object
{ "street": "200 SportingGreen",
"city": "South San Francisco",
"state": "CA",
"zipCode": 99236,
"country": “USA"
}
$LineItems Array
[ { "ItemNumber" : 1,
"Part" : {
"Description" : “Christmas”
"UPCCode" : 13131092899 }
},
{ "ItemNumber" : 2,
"Part" : {
"Description" : “Easter”
"UPCCode" : 13131092899 }
]

 Compatible with Java Script
 $.phone[0]
 Wildcards, Multi-Selects, Ranges
 $.phone[*], $.phone[0,1 5 to 9]
 Predicates
 .address?(.zip > $zip)
 SQL conversion functions usable in predicates
 .?(to_date(.date) > $date)

 JSON_VALUE
 Return a single scalar value from a JSON Document
 JSON_QUERY
 Return a JSON Object or JSON Array from a JSON Document
 JSON_EXISTS
 Filter rows based on JSON-PATH expressions
 JSON_TABLE
 Project in-line, nested relational views from JSON Documents
 JSON_TEXTCONTAINS
 JSON aware full-text searching of JSON Documents
Proposed extension to SQL standards

 Using .dotted notation
SQL> select j.PO_DOCUMENT
2 from J_PURCHASEORDER j
3 where j.PO_DOCUMENT.PONumber = 1600
4 /
SQL> select j.PO_DOCUMENT.ShippingInstructions.Address
2 from J_PURCHASEORDER j
3 where j.PO_DOCUMENT.PONumber = 1600
4 /

 Can only return a SCALAR value
SQL> select JSON_VALUE(PO_DOCUMENT,
2 '$.LineItems[0].Part.UnitPrice'
3 returning NUMBER(5,3))
4 from J_PURCHASEORDER p
5 where JSON_VALUE(PO_DOCUMENT,
6 '$.PONumber' returning NUMBER(10)) = 1600 ;

 Can only returns an ARRAY or OBJECT (= JSON content)
SELECT JSON_QUERY('{a:100, b:200, c:300}', '$.*' WITH WRAPPER)
AS value
FROM DUAL;
VALUE
--------------------------------------------------------------------------------
[100,200,300]

 Used in theWHERE clause
SQL> select count(*)
2 from J_PURCHASEORDER
3 where JSON_EXISTS( PO_DOCUMENT
4 , '$.ShippingInstructions.Address.state')
5 /

 Used in the FROM clause
 Creation of an inline relational view of JSON
SQL> SELECT m.*
2 FROM J_PURCHASEORDER p
3 , JSON_TABLE
4 ( p.PO_DOCUMENT, '$'
5 columns
6 po_rno FOR ORDINALITY,
7 po_number NUMBER(10) path '$.PONumber'
8 ) m
9 WHERE po_number > 1600 and PO_Number < 1605;

SQL> SELECT m.*
2 FROM J_PURCHASEORDER p
3 , JSON_TABLE
4 ( p.PO_DOCUMENT, '$'
5 columns
6 po_number NUMBER(10) path '$.PONumber',
7 reference VARCHAR2(30) path '$.Reference',
8 requestor VARCHAR2(32) path '$.Requestor',
9 userid VARCHAR2(10) path '$.User',
10 center VARCHAR2(16) path '$.CostCenter'
11 ) m
12 WHERE po_number > 1600 and PO_Number < 1605;

 1 row output for each row in table
PO_NUMBER REFERENCE REQUSTOR USERID CENTER
1600 ABULL-20140421 Alexis Bull ABULL A50
1603 KCHUNG-20141022 Kelly Chung KCHUNG A50
1604 LBISSOT-20141009 Laura Bissot LBISSOT A50

create or replace view J_PURCHASEORDER_DETAIL_VIEW as
select d.*
from J_PURCHASEORDER p,
JSON_TABLE
(p.PO_DOCUMENT, '$'
columns (
PO_NUMBER NUMBER(10) path '$.PONumber',
USERID VARCHAR2(10) path '$.User',
COSTCENTER VARCHAR2(16) path '$.CostCenter',
NESTED PATH '$.LineItems[*]'
columns
( ITEMNO NUMBER(38) path '$.ItemNumber',
UNITPRICE NUMBER(14,2) path '$.Part.UnitPrice'
) ) ) d;

 NULL on ERROR
 The Default
 Return NULL instead of raising the error
 ERROR on ERROR
 Raise the error (no special handling)
 TRUE ON ERROR
 In JSON_EXISTS
 ReturnTRUE instead of raising the error

 FALSE ON ERROR
 In JSON_EXISTS
 Return FALSE instead of raising the error
 EMPTY ON ERROR
 In JSON_QUERY
 Return an empty array ([]) instead of raising the error
 DEFAULT 'literal_value' ON ERROR
 Return the specified value instead of raising the error

 RETURNING clause
 PRETTY
▪ Can only be used in JSON_QUERY
▪ Pretty-print the returned data
 ASCII
▪ Can only be used in JSON_VALUE, JSON_QUERY
▪ Automatically escape all non-ASCII Unicode characters in the returned data,
using standard ASCII Unicode

 JSON_TABLE, JSON_QUERY
 without WRAPPER clause
▪ DEFAULT, no change
▪ Raise error, if scalar/multiple values in non JSON result
 WITH WRAPPER
▪ Wrap result as a JSON ARRAY [ ]
 WITH CONDITIONAL WRAPPER
▪ Wrap result as a JSON ARRAY [ ]
▪ Don’t wrap result if scalar/multiple values in JSON result

JSON
Example
WITH WRAPPER WITHOUT
WRAPPER
WITH CONDITIONAL
WRAPPER
{"id": 38327}
(single object)
[{"id": 38327}] {"id": 38327} {"id": 38327}
[42, "a", true]
(single array)
[[42, "a", true]] [42, "a", true] [42, "a", true]
42 [42] Error
(scalar)
[42]
42, "a", true [42, "a", true] Error
(multiple values)
[42, "a", true]
none [] Error
(no values)
[]
For a single JSON object or array value, it is the same as WITHOUT WRAPPER.

 JSON_TABLE
 FORMAT JSON
▪ Forces JSON_QUERY behavior
▪ Therefore can have an explicit wrapper clause
 Default
▪ Projection like JSON_VALUE

create unique index PO_NUMBER_IDX
on J_PURCHASEORDER
(JSON_VALUE ( PO_DOCUMENT, '$.PONumber'
returning NUMBER(10)
ERRORON ERROR));
create bitmap index COSTCENTER_IDX
on J_PURCHASEORDER
(JSON_VALUE (PO_DOCUMENT, '$.CostCenter'));

 Full-text search of JSON data that is stored in aVARCHAR2,
BLOB, or CLOB column
 Must be used in conjunction with special JSON OracleText
Index
 Use CTXSYS.JSON_SECTION_GROUP

 Improvements
 Generate JSON
 PL/SQL support for JSON
 JSON Dataguide
 In-Memory Column support for JSON
 Materialized view support for JSON
 …for In-Memory Column support…

 JSON documentation has its own manual
 “JSON Developers Guide”
 The JSON chapter in the “XMLDB Developers Guide” has been
removed
 Last version has approximately 200 pages

 You can use CREATE SEARCH INDEX with keywords FOR
JSON to create a search index, a dataguide, or both at the
same time.The default behavior is to create both.
 CREATE SEARCH INDEX … FOR JSON
 In “Parameters” clause
▪ SEARCH_ON NONE (disable search)
▪ DATAGUIDE ON
 ALTER INDEX … REBUILD

 Support for
 ARRAYS
 ARRAY ELEMENTS

 JSON_VALUE, JSON_TABLE support for
 DATE
 TIMESTAMP
 TIMESTAMP WITHTIMEZONE
 SDO_GEOMETRY
▪ GeoJSON objects
 PL/SQL
 Added SQL/JSON Functions and Conditions
functionality

 JSON_ARRAY
 JSON_OBJECT
 JSON_ARRAYAGG
 JSON_OBJECTAGG

 Returns each row of data generated by
the SQL query as a JSON array.

 Returns each row of data generated by
the SQL query as a JSON object

 Aggregate generated JSON arrays

 Aggregate generated JSON objects

 JSON_ELEMENT_T
 Supertype of the other JSON object types
 JSON_OBJECT_T
 Subtype used to hold JSON objects
 JSON_ARRAY_T
 Subtype used to hold JSON arrays
 JSON_SCALAR_T
 Subtype used for scalar JSON values
 JSON_KEY_LIST
 a varray ofVARCHAR2(4000)

 Parsing
 “parse”
▪ accepts varchar2, CLOB, BLOB  output JSON tekst  JSON element
 Serialization
 “to_”
▪ to_string( )  returns string (varchar2) representation of JSON object

 Getter / Setter
For JSON_OBJECT_T and JSON_ARRAY_T
 obtain (“getter”)
▪ get( )  returns a reference
▪ “get_”  returns a copy, via for example “get_clob( )”
 update (“setter”)
▪ put ( )  update an object or array instance
▪ put_null ( )  sets object or array to NULL value
▪ append ( )  adds a new element at the end of the array
(forJSON_ARRAY only)

 Introspection
 “is_”  checks object, array, scalar, string, number
(returns boolean)
 get_size( )  returns the number of members
 get_type( )  returns the JSON type
 get_keys( )  returns an instance of JSON_KEY_LIST
 Other
 remove ( )  remove the object member or array element
 clone ( )  create and return copy of the object or array

 A JSON dataguide lets you discover
information about the structure and
content of JSON documents stored in
Oracle Database.
 Manually via DBMS_JSON package

 Create JSON schema document
 Create views
 Automatically add or update virtual
columns
 MAX_STRING_SIZE = EXTENDED
 JSON combined with DG / DBIM
  OSON (DBIM JSON Binary Format)
 Search optimization
 Pre-validate, type-check or exclude content
before insert

 compatible = 12.2.0.0
 inmemory_expressions_usage
 Set to either ENABLE | STATIC_ONLY
 inmemory_expressions_usage =
 ENABLE
 inmemory_virtual_columns =
 ENABLE
 inmemory_size
 Size large enough to hold objects in memory

 What is JSON?
 Oracle 12.1.0.2
 Load & Store
▪ JSON conditions
 Select
▪ JSON Path Expressions
▪ JSON Operators and Functions
 Index
 Oracle 12.2.0.1
 Generate
▪ JSON functions
▪ PL/SQL JSON Support
 Automate
▪ Dataguide
 Improve performance via DBIM
▪ In-Memory Expressions

 Oracle Database SQL Language
Reference
 JSON Functions
▪ JSON_QUERY
▪ JSON_TABLE
▪ JSON_VALUE
 JSON Conditions
▪ IS JSON
▪ JSON_EXISTS
▪ JSON_TEXTCONTAINS
 Oracle XMLDB Developers
Guide
 JSON in DB 12.1.0.2
 JSON Path Expressions
▪ Syntax
 Indexing JSON
▪ Syntax
 Loading JSON
▪ A Method
 JSON on xmldb.nl

 Stanford - Introduction to Databases (JSON)
 Eclipse JSON Editor Plugin
 JSONView addon (Firefox/Chrome)
 JSON Schema
 Get StartedWith JSON
 www.json-generator.com
 JSON Datasets: www.data.gov

Oracle Database - JSON and the In-Memory Database

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