SqTypeRow

SqTypeRow is derived from SqTypeJoint. It can create instance of SqRow and parse unknown (or known) result, table, and column.
SqTypeRow sample code is in storage-row.cpp
Note: SqTypeRow is in sqxcsupport library (sqxcsupport.h).

SqType
│
└─── SqTypeJoint
     │
     └─── SqTypeRow

Directly use without setup

SQ_TYPE_ROW is build-in static constant type for SqTypeRow, user can use it to parse unknown result directly. In this case, all data type in SqRow is C string because SqTypeRow don't know type of columns.

use C language

	SqRow      *row;
	SqPtrArray *array;

	// specify the table type as SQ_TYPE_ROW
	row = sq_storage_get(storage, "users", SQ_TYPE_ROW, 11);

	// specify the table type as SQ_TYPE_ROW
	// specify the container type of returned data as SQ_TYPE_PTR_ARRAY
	array = sq_storage_query(storage, query, SQ_TYPE_ROW, SQ_TYPE_PTR_ARRAY);

use C++ language

	Sq::Row      *row;
	Sq::PtrArray *array;

	// specify the table type as SQ_TYPE_ROW
	row = (Sq::Row*) storage->get("users", SQ_TYPE_ROW, 11);

	// specify the table type as SQ_TYPE_ROW
	// specify the container type of returned data as SQ_TYPE_PTR_ARRAY
	array = (Sq::PtrArray*) storage->query(query, SQ_TYPE_ROW, SQ_TYPE_PTR_ARRAY);

Create and setup

If you want get correct data type from SqRow, you must create dynamic SqTypeRow and setup it. Because the parser of SqTypeRow must know type of columns in table, user must add, remove, clear tables in SqTypeRow.
You can specify table alias name (used by SQL AS keyword) in the last argument when you add or remove tables. If alias name is NULL, Sqxc use table name directly.

use C language

	SqTypeRow *type  = sq_type_row_new();
	SqTable   *table = table_instance;

	sq_type_row_add(type, table, "tableAsName");

	sq_type_row_remove(type, table2, "table2AsName");

	sq_type_row_clear(type);

use C++ language

	Sq::TypeRow *type  = new Sq::TypeRow();
	Sq::Table   *table = table_instance;

	type->add(table, "tableAsName");

	type->remove(table2, "table2AsName");

	type->clear();

Works with SqStorage

You can use SqTypeRow to replace default joint type in SqStorage:

	Sq::TypeRow   *typeRow     = new Sq::TypeRow();
	Sq::TypeJoint *typeDefault = storage->joint_default;
	storage->joint_default = typeRow;
	delete typeDefault;

When SqTypeRow is default joint type, the element type of query() result is SqRow in the following cases:

'query' has joined multi-table.
'query' has unknown table or unknown result.

Example: Build query and get result:
The first table in the query is "cities" and the second table is "users".

SELECT * FROM cities JOIN users ON cities.id = users.city_id

use C++ language

	std::vector<Sq::Row> *vector;

	query->from("cities")->join("users", "cities.id", "=", "users.city_id");

	vector = storage->query<std::vector<Sq::Row>>(query);

	for (unsigned int index = 0;  index < vector->size();  index++) {
		// get Sq::Row from std::vector
		Sq::Row &row = vector->at(index);
		// handle columns in Sq::Row
		for (unsigned int nth = 0;  nth < row.length;  nth++) {
			std::cout << row.cols[nth].name << " = ";
			// column value type is decided by 'row.cols[nth].type'
			if (row.cols[nth].type == SQ_TYPE_INT)
				std::cout << row.data[nth].int_ << std::endl;
			if (row.cols[nth].type == SQ_TYPE_STR)
				std::cout << row.data[nth].str  << std::endl;
			// other type...
		}
	}

If you don't want to change default joint type:

call sq_storage_setup_query() to setup SqQuery and SqTypeRow。.
call sq_storage_query() with SqTypeRow.
If you skip step 1, all data type in SqRow is C string because SqTypeRow don't know type of column.

function sq_storage_setup_query() declarations:

// C function
SqType* sq_storage_setup_query(SqStorage *storage, SqQuery *query, SqTypeJoint *typeJoint);

// C++ method
Sq::Type *StorageMethod::setupQuery(Sq::QueryMethod &query, Sq::TypeJointMethod *typeJoint);

It setup 'query' and 'typeJoint' then return SqType for calling sq_storage_query().
It will add "SELECT table.column AS 'table.column'" in 'query' if 'query' has joined multi-table.

Return value	Description
NULL	if table not found and 'typeJoint' can NOT parse unknown table type.
'typeJoint'	if 'query' has joined multi-table. It will setup 'typeJoint' and 'query'.
type of table	if 'query' has only 1 table. It will setup 'typeJoint' but keep 'query' no change. In this case, user can call sq_storage_query() with returned type or 'typeJoint'.

use C functions

	SqType *typeContainer = NULL;

	sq_storage_setup_query(storage, query, typeRow);
	container = sq_storage_query(storage, query, typeRow, typeContainer);

use C++ methods

	Sq::Type *typeContainer = NULL;

	storage->setupQuery(query, typeRow);
	container = storage->query(query, typeRow, typeContainer);

use C++ STL

	storage->setupQuery(query, typeRow);
	vector = storage->query<std::vector<Sq::Row>>(query, typeRow);

黃正雄 / 思库可思 sqxclib

SqTypeRow

Directly use without setup

Create and setup

Works with SqStorage

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SqTypeRow

Directly use without setup

Create and setup

Works with SqStorage

简介

发行版 (11)

贡献者

近期动态

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黃正雄 / 思库可思 sqxclib