Template base class for doing a join. More...
#include "rdm_db_query.h"
![Inheritance graph](class_r_d_m_1_1_d_b_1_1_q_u_e_r_y_1_1join__rows__inherit__graph.png)
Public Member Functions |
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join_rows () | |
~join_rows () | |
uint32_t | init_tables_to_write_lock (RDM_TABLE_ID *tables) |
IDs of the tables where rows are inserted. More... |
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uint32_t | init_tables_to_read_lock (RDM_TABLE_ID *tables) |
IDs of the tables where rows are read. More... |
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RDM_RETCODE | init (RDM_DB db) |
Initialize this object. More... |
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void | reset (void) |
Reset this object. More... |
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RDM_RETCODE | fetch_first () |
Fetch the first. More... |
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RDM_RETCODE | fetch_prev () |
Fetch the previous. More... |
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RDM_RETCODE | fetch_next () |
Fetch the next. More... |
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RDM_RETCODE | fetch_last () |
Fetch the last. More... |
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template<class TARGET_ROW_T > | |
RDM_RETCODE | bind_row (TARGET_ROW_T *target_row, bool *target_all_columns_null=NULL) |
Bind a row. More... |
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Static Public Member Functions |
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constexpr static int | number_of_tables_to_write_lock (void) |
Number of tables where rows are inserted. More... |
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constexpr static int | number_of_tables_to_read_lock (void) |
Number of tables where rows are read. More... |
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Data Fields |
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NEXT | next |
Protected Member Functions |
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virtual RDM_RETCODE | setup_cursor_for_join (RDM_CURSOR cursor)=0 |
Set up the cursor for the join. More... |
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virtual RDM_RETCODE | fetch (direction dir, bool first_or_last)=0 |
Fetch a row. More... |
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Protected Attributes |
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RDM_DB | db |
RDM_CURSOR | cursor |
void * | target_row |
uint32_t | target_size |
bool * | target_all_columns_null |
bool | outer_join |
position | pos |
Detailed Description
template<RDM_TABLE_ID table_id, class NEXT>
class RDM::DB::QUERY::join_rows< table_id, NEXT >
Template base class for doing a join.
Don't use this template class directly. Instead, use one of the derived classes.
- Template Parameters
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table_id The ID of the table NEXT The class in the chain to fetch data from
Constructor & Destructor Documentation
join_rows()
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inline |
~join_rows()
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inline |
References RDM::DB::QUERY::join_rows< table_id, NEXT >::cursor, and rdm_cursorFree().
![](class_r_d_m_1_1_d_b_1_1_q_u_e_r_y_1_1join__rows_a0a22fc322b5db6bb75a66ff9e85ee0f1_cgraph.png)
Member Function Documentation
bind_row()
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inline |
Bind a row.
Bind an application target row. For each row or set of rows that are fetched, one actual row in that set will be populated into the buffers specified here unless all columns are 'null' in the case of no matching rows.
Two buffers can be provided. One buffer for the actual row data and another buffer with a boolean that is set to the boolean value 'true', if all columns are 'null' due to an outer join, where there were no matching rows.
Be aware that when there are no matching rows, the target row will not be updated at all. Therefore, an application should always provide a buffer with a boolean for the second parameter in the case of an outer join.
To get the result of all rows in the set of rows that are calculated by a give chain of classes, the bind_row methode for each class in that chain should be called. Each of these buffers will only be populated when the corresponding class does a fetch. Therefore, care should be taken to not overwrite any of these buffers with other data between each fetch.
- Template Parameters
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TARGET_ROW_T The type for the application target row struct definition
- Parameters
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[in] target_row The target the rows are fetched into [in] target_all_columns_null Whether all the columns are NULL due to the extra row needed for outer joins
References sOKAY, RDM::DB::QUERY::join_rows< table_id, NEXT >::target_all_columns_null, RDM::DB::QUERY::join_rows< table_id, NEXT >::target_row, and RDM::DB::QUERY::join_rows< table_id, NEXT >::target_size.
fetch()
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protectedpure virtual |
Fetch a row.
Fetch a row or combination of rows for what the actual class is computing. This navigation may be done based on a previously set position, and a new position will be establshed for a successful return.
This method must be implemented in the derived classes.
- Return values
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sOKAY Normal, successful return. sENDOFCURSOR Reached the end of the cursor collection. eINVITERATION Invalid attempt to move cursor before 'BeforeFirst' or past 'AfterLast'. eNOSTARTREAD A read operation was attempted when no rdm_dbStartSnapshot(), rdm_dbStartRead(), or rdm_dbStartUpdate() is active. eNOTLOCKED Attempt to access a table for reading or update without proper locks. eDBNOTOPEN Database not open. eCATMISMATCH Catalog in memory does not match Catalog on disk. eNOCURRENTROW The cursor is not positioned to a valid row. eOWNERDELETED The owner row for a set cursor has been deleted. eSINGLETONDELETED The row for a singleton cursor has been deleted.
- Parameters
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[in] dir The direction we are fetching [in] first_or_last Wheter we are fetching one of the extremes such as the first or the last as opposed to the next or the previous
Referenced by RDM::DB::QUERY::join_rows< table_id, NEXT >::fetch_first(), RDM::DB::QUERY::join_rows< table_id, NEXT >::fetch_last(), RDM::DB::QUERY::join_rows< table_id, NEXT >::fetch_next(), and RDM::DB::QUERY::join_rows< table_id, NEXT >::fetch_prev().
![](class_r_d_m_1_1_d_b_1_1_q_u_e_r_y_1_1join__rows_a67a826aff0ee4246a134cb3eba6bf020_icgraph.png)
fetch_first()
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inline |
Fetch the first.
Fetch the first row or combination of rows for what the actual class is computing. This navigation is done independent of any previously set position. A new position will be establshed for a successful return.
- Return values
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sOKAY Normal, successful return. sENDOFCURSOR Reached the end of the cursor collection. eINVITERATION Invalid attempt to move cursor before 'BeforeFirst' or past 'AfterLast'. eNOSTARTREAD A read operation was attempted when no rdm_dbStartSnapshot(), rdm_dbStartRead(), or rdm_dbStartUpdate() is active. eNOTLOCKED Attempt to access a table for reading or update without proper locks. eDBNOTOPEN Database not open. eCATMISMATCH Catalog in memory does not match Catalog on disk. eNOCURRENTROW The cursor is not positioned to a valid row. eOWNERDELETED The owner row for a set cursor has been deleted. eSINGLETONDELETED The row for a singleton cursor has been deleted.
References RDM::DB::direction_forward, RDM::DB::QUERY::join_rows< table_id, NEXT >::fetch(), sNULLVAL, and sOKAY.
![](class_r_d_m_1_1_d_b_1_1_q_u_e_r_y_1_1join__rows_ae65e26e18c9bb625d03fd2432169bc81_cgraph.png)
fetch_last()
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inline |
Fetch the last.
Fetch the last row or combination of rows for what the actual class is computing. This navigation is done independent of any previously set position. A new position will be establshed for a successful return.
- Return values
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sOKAY Normal, successful return. sENDOFCURSOR Reached the end of the cursor collection. eINVITERATION Invalid attempt to move cursor before 'BeforeFirst' or past 'AfterLast'. eNOSTARTREAD A read operation was attempted when no rdm_dbStartSnapshot(), rdm_dbStartRead(), or rdm_dbStartUpdate() is active. eNOTLOCKED Attempt to access a table for reading or update without proper locks. eDBNOTOPEN Database not open. eCATMISMATCH Catalog in memory does not match Catalog on disk. eNOCURRENTROW The cursor is not positioned to a valid row. eOWNERDELETED The owner row for a set cursor has been deleted. eSINGLETONDELETED The row for a singleton cursor has been deleted.
References RDM::DB::direction_backward, RDM::DB::QUERY::join_rows< table_id, NEXT >::fetch(), sNULLVAL, and sOKAY.
![](class_r_d_m_1_1_d_b_1_1_q_u_e_r_y_1_1join__rows_a6b59d313b93bc57e6acb8d23c778d134_cgraph.png)
fetch_next()
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inline |
Fetch the next.
Fetch the next row or combination of rows for what the actual class is computing. This navigation is done based on a previously set position, and a new position will be establshed for a successful return.
- Return values
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sOKAY Normal, successful return. sENDOFCURSOR Reached the end of the cursor collection. eINVITERATION Invalid attempt to move cursor before 'BeforeFirst' or past 'AfterLast'. eNOSTARTREAD A read operation was attempted when no rdm_dbStartSnapshot(), rdm_dbStartRead(), or rdm_dbStartUpdate() is active. eNOTLOCKED Attempt to access a table for reading or update without proper locks. eDBNOTOPEN Database not open. eCATMISMATCH Catalog in memory does not match Catalog on disk. eNOCURRENTROW The cursor is not positioned to a valid row. eOWNERDELETED The owner row for a set cursor has been deleted. eSINGLETONDELETED The row for a singleton cursor has been deleted.
References RDM::DB::direction_forward, RDM::DB::QUERY::join_rows< table_id, NEXT >::fetch(), sNULLVAL, and sOKAY.
![](class_r_d_m_1_1_d_b_1_1_q_u_e_r_y_1_1join__rows_a86276e4999f1efa1d229ede93d2c7c4f_cgraph.png)
fetch_prev()
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inline |
Fetch the previous.
Fetch the previous row or combination of rows for what the actual class is computing. This navigation is done based on a previously set position, and a new position will be establshed for a successful return.
- Return values
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sOKAY Normal, successful return. sENDOFCURSOR Reached the end of the cursor collection. eINVITERATION Invalid attempt to move cursor before 'BeforeFirst' or past 'AfterLast'. eNOSTARTREAD A read operation was attempted when no rdm_dbStartSnapshot(), rdm_dbStartRead(), or rdm_dbStartUpdate() is active. eNOTLOCKED Attempt to access a table for reading or update without proper locks. eDBNOTOPEN Database not open. eCATMISMATCH Catalog in memory does not match Catalog on disk. eNOCURRENTROW The cursor is not positioned to a valid row. eOWNERDELETED The owner row for a set cursor has been deleted. eSINGLETONDELETED The row for a singleton cursor has been deleted.
References RDM::DB::direction_backward, RDM::DB::QUERY::join_rows< table_id, NEXT >::fetch(), sNULLVAL, and sOKAY.
![](class_r_d_m_1_1_d_b_1_1_q_u_e_r_y_1_1join__rows_a705c28c3f2dd8a1a9f4824524a6f76bf_cgraph.png)
init()
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inline |
Initialize this object.
Call this method before querying for any data.
- Return values
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sOKAY Normal, successful return. eINVARG Invalid argument. eDBNOTOPEN Database not open. eCURSORDB Cursor is associated with a different database. ePRECOMMITTED A precommitted transaction must be committed or rolled back before further operations on this database are allowed.
- Parameters
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db [IN] Use this database for chained classes that need to insert rows
References RDM::DB::QUERY::join_rows< table_id, NEXT >::db, RDM::DB::QUERY::join_rows< table_id, NEXT >::next, and sOKAY.
init_tables_to_read_lock()
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inline |
IDs of the tables where rows are read.
Use this method to initialize an array of table IDs. This array can then be used to start a transaction where those tables are specified for locking.
References RDM::DB::QUERY::join_rows< table_id, NEXT >::next.
init_tables_to_write_lock()
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inline |
IDs of the tables where rows are inserted.
Use this method to initialize an array of table IDs. This array can then be used to start a transaction where those tables are specified.
References RDM::DB::QUERY::join_rows< table_id, NEXT >::next.
number_of_tables_to_read_lock()
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inlinestaticconstexpr |
number_of_tables_to_write_lock()
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inlinestaticconstexpr |
reset()
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inline |
Reset this object.
Call this method to discard internally kept state and get ready to query data again.
Any alternative implementation of this method in a sub class would call this method to reset the next class.
References RDM::DB::QUERY::join_rows< table_id, NEXT >::db, RDM::DB::QUERY::join_rows< table_id, NEXT >::next, RDM::DB::QUERY::join_rows< table_id, NEXT >::pos, and RDM::DB::QUERY::POS_NOT_SET.
setup_cursor_for_join()
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protectedpure virtual |
Set up the cursor for the join.
This methode is called each time we have a row fetched from the next class in the chain of classes. It must be implemented in the derived classes. For each of these calls, join_rows::cursor is associated with the rows in the join result for this class.
For cases that can return more than one row, the cursor has to be positioned at the before first position. For cases that can only return zero or one row, the cursor has to be positioned at the row and return an error code of eENDOFCURSOR if there are no rows.
- Return values
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sOKAY Normal, successful return. sENDOFCURSOR Reached the end of the cursor collection. eNOSTARTREAD A read operation was attempted when no rdm_dbStartSnapshot(), rdm_dbStartRead(), or rdm_dbStartUpdate() is active. eNOTLOCKED Attempt to access a table for reading or update without proper locks. eCURSORDB Cursor is associated with a different database. eDBNOTOPEN Database not open. eINVKEYID Invalid key id. eISRTREE The key specified is an rtree index. ePRECOMMITTED A precommitted transaction must be committed or rolled back before further operations on this database are allowed.
- Parameters
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cursor [IN] A cursor with the row we fetched from the next class
Field Documentation
cursor
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protected |
The cursor we use for navigating and reading rows
Referenced by RDM::DB::QUERY::join_rows< table_id, NEXT >::~join_rows().
db
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protected |
The database we use for reading
Referenced by RDM::DB::QUERY::join_rows< table_id, NEXT >::init(), and RDM::DB::QUERY::join_rows< table_id, NEXT >::reset().
next
NEXT RDM::DB::QUERY::join_rows< table_id, NEXT >::next |
The next class we receive rows from
Referenced by RDM::DB::QUERY::join_rows< table_id, NEXT >::init(), RDM::DB::QUERY::join_rows< table_id, NEXT >::init_tables_to_read_lock(), RDM::DB::QUERY::join_rows< table_id, NEXT >::init_tables_to_write_lock(), and RDM::DB::QUERY::join_rows< table_id, NEXT >::reset().
outer_join
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protected |
Wheter this is an outer join or not
Referenced by RDM::DB::QUERY::inner_join_by_key< table_id, key_id, KEY_T, NEXT >::inner_join_by_key(), RDM::DB::QUERY::inner_join_by_reference< table_id, ref_id, NEXT >::inner_join_by_reference(), RDM::DB::QUERY::inner_join_by_referenced< table_id, ref_id, NEXT >::inner_join_by_referenced(), RDM::DB::QUERY::inner_join_by_referencing< table_id, ref_id, NEXT >::inner_join_by_referencing(), RDM::DB::QUERY::outer_join_by_key< table_id, key_id, KEY_T, NEXT >::outer_join_by_key(), RDM::DB::QUERY::outer_join_by_reference< table_id, ref_id, NEXT >::outer_join_by_reference(), RDM::DB::QUERY::outer_join_by_referenced< table_id, ref_id, NEXT >::outer_join_by_referenced(), and RDM::DB::QUERY::outer_join_by_referencing< table_id, ref_id, NEXT >::outer_join_by_referencing().
pos
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protected |
The current position as a result of the last fetch
Referenced by RDM::DB::QUERY::join_rows< table_id, NEXT >::reset().
target_all_columns_null
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protected |
The target "all columns null" for each fetch we do
Referenced by RDM::DB::QUERY::join_rows< table_id, NEXT >::bind_row().
target_row
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protected |
The target row for each fetch we do
Referenced by RDM::DB::QUERY::join_rows< table_id, NEXT >::bind_row().
target_size
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protected |
The size of the target row
Referenced by RDM::DB::QUERY::join_rows< table_id, NEXT >::bind_row().
The documentation for this class was generated from the following file: