Initial commit

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{\fonttbl\f0\fswiss\fcharset0 Helvetica;}

{\colortbl;\red255\green255\blue255;}

\margl1440\margr1440\vieww9000\viewh8400\viewkind0

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\f0\fs24 \cf0 No work files for this lesson...}

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SET LINES 3000

SET PAGES 3000

SET LONG 3000

SET TRIMSPOOL ON

SET SQLFORMAT ANSICONSOLE

SET FEED 1

--

-- JSON_QUERY used as predicate in plan

-- cost = 1 and 1 for dot notation

--

EXPLAIN PLAN FOR

SELECT jd.json_col.Name

  FROM json_data jd

 WHERE jd.json_col.Name = 'Marty';

SELECT *

  FROM TABLE(DBMS_XPLAN.DISPLAY);

--

-- Virtual Column used as predicate in plan (cost = 1 and 1)

-- cost = 1 and 1 for dot notation

--

SELECT /*+ GATHER_PLAN_STATISTICS */ jd.json_col.Name

  FROM json_data jd

 WHERE jd.json_col.Name = 'Marty';

SELECT *

  FROM table(DBMS_XPLAN.DISPLAY_CURSOR(FORMAT=>'ALLSTATS LAST'));

--

-- JSON Dot Notation index

--

CREATE INDEX zebra_name_ix ON json_data jd ( jd.json_col.Name );

DROP INDEX zebra_name_ix;

CREATE INDEX zebra_name_ix ON json_data jd ( JSON_VALUE(jd.json_col,'$.Name' RETURNING VARCHAR2(30)) );

--

-- Virtual Column used as predicate in plan (cost = 1 and 1)

-- cost = 1 and 1 json_value

--

SELECT /*+ GATHER_PLAN_STATISTICS */ jd.json_col.Name

  FROM json_data jd

 WHERE JSON_VALUE(jd.json_col,'$.Name' RETURNING VARCHAR2(30)) = 'Marty';

SELECT /*+ GATHER_PLAN_STATISTICS */ jd.json_col.Name

  FROM json_data jd

 WHERE JSON_EXISTS(jd.json_col,'$.Name');

CREATE INDEX has_name_column ON json_data jd ( JSON_EXISTS(jd.json_col,'$.Name') );

SELECT *

  FROM table(DBMS_XPLAN.DISPLAY_CURSOR(FORMAT=>'ALLSTATS LAST'));

SELECT index_name,

       column_name

  FROM user_ind_columns

 WHERE index_name = 'HAS_NAME_COLUMN';

--

-- Note that it includes FALSE ON ERROR so broken JSON will always return FALSE

--

SELECT data_type,

       data_length,

       data_default

  FROM user_tab_cols

 WHERE column_name = ( SELECT column_name

                         FROM user_ind_columns

                        WHERE index_name = 'HAS_NAME_COLUMN' );

SET LINES 3000

SET PAGES 3000

SET SQLFORMAT ANSICONSOLE

EXPLAIN PLAN FOR

SELECT jd.json_col.Name

  FROM json_data jd

 WHERE jd.json_col.Name = 'Marty';

SELECT *

  FROM TABLE(DBMS_XPLAN.DISPLAY)

 WHERE TRIM(plan_table_output) IS NOT NULL;

CREATE INDEX zebra_name_ix ON json_data jd ( jd.json_col.Name );

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SET LINES 3000

SET PAGES 3000

SET SQLFORMAT ANSICONSOLE

COLUMN index_name FORMAT a15

COLUMN column_name FORMAT a15

EXPLAIN PLAN FOR

SELECT jd.json_col.Name

  FROM json_data jd

 WHERE jd.json_col.Name = 'Marty';

SELECT *

  FROM TABLE(DBMS_XPLAN.DISPLAY)

 WHERE TRIM(plan_table_output) IS NOT NULL;

--

-- gets created as an JSON_QUERY call and used as such

--

CREATE INDEX zebra_name_ix ON json_data jd ( jd.json_col.Name );

SELECT index_name,

       column_name

  FROM user_ind_columns

 WHERE index_name = 'ZEBRA_NAME_IX';

SELECT data_type,

       data_length,

       data_default

  FROM user_tab_cols

 WHERE column_name = ( SELECT column_name

                         FROM user_ind_columns

                        WHERE index_name = 'ZEBRA_NAME_IX' );

--

-- Recreate with smaller data length. Dot notation queries may not use it anymore...

--

DROP INDEX zebra_name_ix;

CREATE INDEX zebra_name_ix ON json_data jd ( JSON_QUERY("JSON_COL" FORMAT JSON , '$.Name' RETURNING VARCHAR2(30) ASIS  WITHOUT ARRAY WRAPPER NULL ON ERROR));

--

-- Index is updated when row is created. Be careful of the ON ERROR clause. It may cause DML to fail

--

DROP INDEX zebra_name_ix;

CREATE INDEX zebra_name_ix ON json_data jd ( JSON_QUERY("JSON_COL" FORMAT JSON , '$.Name' RETURNING VARCHAR2(30) ASIS  WITHOUT ARRAY WRAPPER ERROR ON ERROR));

INSERT INTO json_data

VALUES(3,

'{ "Reason" : [ { "Medium" : "Movie",

                  "Title"  : "Zebra With No Name",

                  "Year"   : 2016 } ] }');

--

-- Where clause must match index "closely"

--

DROP INDEX zebra_name_ix;

CREATE INDEX zebra_name_ix ON json_data jd ( JSON_QUERY("JSON_COL" FORMAT JSON , '$.Name' RETURNING VARCHAR2(30) ASIS  WITHOUT ARRAY WRAPPER NULL ON ERROR));

EXPLAIN PLAN FOR

SELECT JSON_QUERY(jd.json_col FORMAT JSON , '$.Name' RETURNING VARCHAR2(30) ASIS  WITHOUT ARRAY WRAPPER NULL ON ERROR)

  FROM json_data jd

 WHERE JSON_QUERY(jd.json_col FORMAT JSON , '$.Name' RETURNING VARCHAR2(30) ASIS  WITHOUT ARRAY WRAPPER NULL ON ERROR) = 'Marty';

SELECT *

  FROM TABLE(DBMS_XPLAN.DISPLAY)

 WHERE TRIM(plan_table_output) IS NOT NULL;

-- what about json value

-- what about json_exists (binary)

-- what about json exists with a value query

DROP INDEX zebra_name_ix;

CREATE INDEX zebra_name_ix ON json_data jd ( JSON_VALUE("JSON_COL", '$.Name' RETURNING VARCHAR2(30)));

EXPLAIN PLAN FOR

SELECT JSON_VALUE(json_col,'$.Name')

  FROM json_data

 WHERE JSON_VALUE(json_col,'$.Name') = 'Marty';

SELECT index_name,

       column_name

  FROM user_ind_columns

 WHERE index_name = 'ZEBRA_NAME_IX';

SELECT data_type,

       data_length,

       data_default

  FROM user_tab_cols

 WHERE column_name = ( SELECT column_name

                         FROM user_ind_columns

                        WHERE index_name = 'ZEBRA_NAME_IX' );

--

-- Use the virtual colum in the where clause!

--

EXPLAIN PLAN FOR

SELECT JSON_VALUE(json_col,'$.Name')

  FROM json_data

 WHERE SYS_NC00003$ = 'Marty';

ALTER TABLE json_data RENAME COLUMN SYS_NC00003$ TO use_index_please;

SELECT JSON_VALUE(json_col,'$.Name')

  FROM json_data

 WHERE use_index_please = 'Marty';

SET PAGES 3000

SET LINES 3000

SET SQLFORMAT ANSICONSOLE

EXPLAIN PLAN FOR

SELECT *

  FROM famous_zebra

 WHERE zebra_name = 'Marty';

SELECT *

  FROM TABLE(DBMS_XPLAN.DISPLAY)

 WHERE plan_table_output IS NOT NULL;

CREATE INDEX zebra_ix ON famous_zebra ( zebra_name );

SELECT index_name,

       column_name

  FROM user_ind_columns

 WHERE index_name = 'ZEBRA_IX';