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TSQLite3Result

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Ivan Semenkov edited this page Oct 24, 2021 · 2 revisions

Table of contents

About

TSQLite3Result class encapsulates the SQLite3 result collection.

uses
  sqlite3.result;
  
type
  TSQLite3Result = class

Create

A new database result can be created by call its constructor.

constructor Create (AErrorsStack : PSQL3LiteErrorsStack; AStatementHandle : 
  psqlite3_stmt; AResCode : Integer);
Example
uses
  libpassqlite, sqlite3.errors_stack, utils.api.cstring, sqlite3.connection;
  
var
  errors : TSQLite3ErrorsStack;
  handle : psqlite3;
  statementHandle : psqlite3_stmt;
  query : API.PAnsiStringWrapper;
  connection : TSQLite3DatabaseConnection;
  res : TSQLite3Result;
  
begin
  errors := TSQLite3ErrorsStack.Create;
  connection := TSQLite3DatabaseConnection.Create(@errors, @handle, 'database',
    [SQLITE_OPEN_CREATE, SQLITE_OPEN_READWRITE]);
  
  query := API.CString.Create('SELECT * FROM sqlite_master;').ToUniquePAnsiChar;
  res := TSQLite3Result.Create(@errors, statementHandle, 
    sqlite3_prepare_v3(handle, query.Value, query.Length,
    SQLITE_PREPARE_NORMALIZE, @statementHandle, nil));
  
  FreeAndNil(res);
  FreeAndNil(query);
  FreeAndNil(connection);
  FreeAndNil(errors);
end;

Iterate

It is possible to iterate for TSQLite3Result rows using in operator. Each value would present as TSQLite3Result.TRowIterator object.

uses
  sqlite3.result;
  
type
  TSQLite3Result = class
  type
    TRowIterator = class
  end;
Example
uses
  libpassqlite, sqlite3.errors_stack, utils.api.cstring, sqlite3.connection;
  
var
  errors : TSQLite3ErrorsStack;
  handle : psqlite3;
  statementHandle : psqlite3_stmt;
  query : API.PAnsiStringWrapper;
  connection : TSQLite3DatabaseConnection;
  res : TSQLite3Result;
  row : TSQLite3Result.TRowIterator;
  
begin
  errors := TSQLite3ErrorsStack.Create;
  connection := TSQLite3DatabaseConnection.Create(@errors, @handle, 'database',
    [SQLITE_OPEN_CREATE, SQLITE_OPEN_READWRITE]);
  
  query := API.CString.Create('SELECT * FROM sqlite_master;').ToUniquePAnsiChar;
  res := TSQLite3Result.Create(@errors, statementHandle, 
    sqlite3_prepare_v3(handle, query.Value, query.Length,
    SQLITE_PREPARE_NORMALIZE, @statementHandle, nil));
  
  for row in res do
    ;
    
  FreeAndNil(res);
  FreeAndNil(query);
  FreeAndNil(connection);
  FreeAndNil(errors);
end;

FirstRow

Retrive the iterator for first row in a TSQLite3Result.

function FirstRow : TRowIterator;
Example
uses
  libpassqlite, sqlite3.errors_stack, utils.api.cstring, sqlite3.connection;
  
var
  errors : TSQLite3ErrorsStack;
  handle : psqlite3;
  statementHandle : psqlite3_stmt;
  query : API.PAnsiStringWrapper;
  connection : TSQLite3DatabaseConnection;
  res : TSQLite3Result;
  row : TSQLite3Result.TRowIterator;
  
begin
  errors := TSQLite3ErrorsStack.Create;
  connection := TSQLite3DatabaseConnection.Create(@errors, @handle, 'database',
    [SQLITE_OPEN_CREATE, SQLITE_OPEN_READWRITE]);
  
  query := API.CString.Create('SELECT * FROM sqlite_master;').ToUniquePAnsiChar;
  res := TSQLite3Result.Create(@errors, statementHandle, 
    sqlite3_prepare_v3(handle, query.Value, query.Length,
    SQLITE_PREPARE_NORMALIZE, @statementHandle, nil));
  
  row := res.FirstRow;
    
  FreeAndNil(res);
  FreeAndNil(query);
  FreeAndNil(connection);
  FreeAndNil(errors);
end;

TRowIterator

HasRow

Return true if iterator has correct row.

function HasRow : Boolean;
Example
uses
  libpassqlite, sqlite3.errors_stack, utils.api.cstring, sqlite3.connection;
  
var
  errors : TSQLite3ErrorsStack;
  handle : psqlite3;
  statementHandle : psqlite3_stmt;
  query : API.PAnsiStringWrapper;
  connection : TSQLite3DatabaseConnection;
  res : TSQLite3Result;
  row : TSQLite3Result.TRowIterator;
  
begin
  errors := TSQLite3ErrorsStack.Create;
  connection := TSQLite3DatabaseConnection.Create(@errors, @handle, 'database',
    [SQLITE_OPEN_CREATE, SQLITE_OPEN_READWRITE]);
  
  query := API.CString.Create('SELECT * FROM sqlite_master;').ToUniquePAnsiChar;
  res := TSQLite3Result.Create(@errors, statementHandle, 
    sqlite3_prepare_v3(handle, query.Value, query.Length,
    SQLITE_PREPARE_NORMALIZE, @statementHandle, nil));
  
  for row in res do
  begin
    if row.HasRow then
      ;
  end;
    
  FreeAndNil(res);
  FreeAndNil(query);
  FreeAndNil(connection);
  FreeAndNil(errors);
end;
NextRow

Retrieve the next entry in a TSQLite3Result.

function NextRow : TRowIterator;
Example
uses
  libpassqlite, sqlite3.errors_stack, utils.api.cstring, sqlite3.connection;
  
var
  errors : TSQLite3ErrorsStack;
  handle : psqlite3;
  statementHandle : psqlite3_stmt;
  query : API.PAnsiStringWrapper;
  connection : TSQLite3DatabaseConnection;
  res : TSQLite3Result;
  row : TSQLite3Result.TRowIterator;
  
begin
  errors := TSQLite3ErrorsStack.Create;
  connection := TSQLite3DatabaseConnection.Create(@errors, @handle, 'database',
    [SQLITE_OPEN_CREATE, SQLITE_OPEN_READWRITE]);
  
  query := API.CString.Create('SELECT * FROM sqlite_master;').ToUniquePAnsiChar;
  res := TSQLite3Result.Create(@errors, statementHandle, 
    sqlite3_prepare_v3(handle, query.Value, query.Length,
    SQLITE_PREPARE_NORMALIZE, @statementHandle, nil));
  
  row := res.FirstRow;
  while row.HasRow do
  begin
  
    row := row.NextRow;
  end;
    
  FreeAndNil(res);
  FreeAndNil(query);
  FreeAndNil(connection);
  FreeAndNil(errors);
end;
Row

Result row.

property Row : TSQLite3ResultRow;

Return TSQLite3ResultRow object.

Example
uses
  libpassqlite, sqlite3.errors_stack, utils.api.cstring, sqlite3.connection;
  
var
  errors : TSQLite3ErrorsStack;
  handle : psqlite3;
  statementHandle : psqlite3_stmt;
  query : API.PAnsiStringWrapper;
  connection : TSQLite3DatabaseConnection;
  res : TSQLite3Result;
  row : TSQLite3Result.TRowIterator;
  
begin
  errors := TSQLite3ErrorsStack.Create;
  connection := TSQLite3DatabaseConnection.Create(@errors, @handle, 'database',
    [SQLITE_OPEN_CREATE, SQLITE_OPEN_READWRITE]);
  
  query := API.CString.Create('SELECT * FROM sqlite_master;').ToUniquePAnsiChar;
  res := TSQLite3Result.Create(@errors, statementHandle, 
    sqlite3_prepare_v3(handle, query.Value, query.Length,
    SQLITE_PREPARE_NORMALIZE, @statementHandle, nil));
  
  row := res.FirstRow;
  while row.HasRow do
  begin
    row.Row;
    
    row := row.NextRow;
  end;
    
  FreeAndNil(res);
  FreeAndNil(query);
  FreeAndNil(connection);
  FreeAndNil(errors);
end;
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