Sql.Database

Unit
Source
Symbols

Symbol	Description
TSqlDatabase	Abstract base class for connections to databases that can be queried using SQL statements.
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///////////////////////////////////////////////////////////////////////////
//                                                                       //
//  Copyright (c) 2015 by Charta Software B.V.                           //
//  All rights reserved                                                  //
//                                                                       //
//  Version:  1.7.0.83525                                                //
//  Web site: https://pascal.chartasoftware.com/                         //
//                                                                       //
//  This code and information are provided "as is" without warranty of   //
//  any kind. Dissemination of this information or reproduction of       //
//  this material is strictly forbidden unless prior written permission  //
//  is obtained from Charta Software B.V..                               //
//                                                                       //
///////////////////////////////////////////////////////////////////////////

unit Sql.Database;

interface

uses
  Boolean,
  Color.Rgb,
  DateTime.Calendar.Gregorian.Date,
  DateTime.Calendar.Gregorian.Instant,
  Decimal,
  FloatingPoint._64,
  Integer,
  Integer._32.Positive,
  Sql.Connection.Settings,
  Sql.Database.PreparedStatement,
  Sql.Expression.Row,
  Sql.Result,
  Sql.Statement,
  Sql.Statement.Executor,
  Sql.Statement.ResultSet,
  Sql.Table.Column,
  Sql.Transaction,
  Stream.Input,
  Text,
  Uuid;

type
  TSqlDatabase = class(TSqlStatementExecutor)
  protected
    function    GetConnectionSettings(): TSqlConnectionSettings; virtual; abstract;
    function    GetCouldConnect(): TBoolean; virtual; abstract;

  public
    procedure   Execute(Statement: TSqlStatement); override;
    procedure   Flush(); override;

  public
    function    Query(Statement: TSqlStatement; ResultMethod: TSqlQueryResultMethod = sqrmStoreResult): TSqlResult; virtual; abstract;
    function    QuerySingleRow(Statement: TSqlStatement): TSqlResult;
    function    Prepare(Statement: TSqlStatement): TSqlPreparedStatement; virtual; abstract;

    function    StartTransaction(): TSqlTransaction; virtual; abstract;
    procedure   EndTransaction(Transaction: TSqlTransaction); virtual; abstract;

    function    ConnectionIdentifier(): TInteger; virtual; abstract;

    function    InsertId(): TInteger; virtual; abstract;
    function    NumberOfAffectedRows(): TInteger; virtual; abstract;

    function    Insert(Statement: TSqlStatement): TInteger;
    function    Exists(Statement: TSqlResultSetStatement): TBoolean;

    // TODO: Table should be a TSqlTable but currently that would introduce a circular reference
    function    SelectOrInsert(Table: TObject; const Columns: array of TSqlTableColumn; Row: TSqlRow): TInteger;

    function    SelectDecimal(Statement: TSqlResultSetStatement): TDecimal;
    function    SelectDecimalWithDefault(Statement: TSqlResultSetStatement; const DefaultValue: TDecimal): TDecimal;
    function    SelectInteger(Statement: TSqlResultSetStatement): TInteger;
    function    SelectIntegerWithDefault(Statement: TSqlResultSetStatement): TInteger; overload;
    function    SelectIntegerWithDefault(Statement: TSqlResultSetStatement; const DefaultValue: TInteger): TInteger; overload;
    function    SelectText(Statement: TSqlResultSetStatement): TText;
    function    SelectTextWithDefault(Statement: TSqlResultSetStatement): TText; overload;
    function    SelectTextWithDefault(Statement: TSqlResultSetStatement; const DefaultValue: TText): TText; overload;
    function    SelectBoolean(Statement: TSqlResultSetStatement): TBoolean;
    function    SelectBooleanWithDefault(Statement: TSqlResultSetStatement; DefaultValue: TBoolean = False): TBoolean;
    function    SelectFloatingPoint(Statement: TSqlResultSetStatement): TFloatingPoint64;
    function    SelectFloatingPointWithDefault(Statement: TSqlResultSetStatement; DefaultValue: TFloatingPoint64 = 0): TFloatingPoint64;
    function    SelectDate(Statement: TSqlResultSetStatement): TGregorianDate;
    function    SelectInstant(Statement: TSqlResultSetStatement): TGregorianInstant;
    function    SelectColor(Statement: TSqlResultSetStatement): TRgbColor;
    function    SelectColorWithDefault(Statement: TSqlResultSetStatement; const DefaultValue: TRgbColor): TRgbColor;
    function    SelectUuid(Statement: TSqlResultSetStatement): TUuid;
    function    SelectUuidWithDefault(Statement: TSqlResultSetStatement; const DefaultValue: TUuid): TUuid;
    function    SelectStream(Statement: TSqlStatement): TInputStream;

    function    IsAlive(): TBoolean; virtual; abstract;
    function    IdleTime(): TPositiveInteger32; virtual; abstract;
    function    UserExists(const Name: TText): TBoolean; virtual; abstract;

    function    TableExists(const Name: TText): TBoolean; virtual; // TODO: Instead of a TableName we should provide a TSqlTable, however, currently this would introduce a circular unit reference
    function    TableHasConstraint(const Table: TText; const Constraint: TText): TBoolean; virtual;
    function    CreateTableDefinition(const SchemaName: TText; const TableName: TText): TObject; // TODO: Instead of a TObject we should return a TSqlTable, however, currently this would introduce a circular unit reference

    // TODO: We return a TObject which actually is a TSqlSystemInformation to prevent circular unit references
    function    GetSystemInformation(): TObject; virtual; abstract;

    function    Embellish(): TSqlDatabase; virtual;

    property    ConnectionSettings: TSqlConnectionSettings read GetConnectionSettings;
    property    CouldConnect: TBoolean read GetCouldConnect;
  end;

implementation

uses
  Byte.Block,
  FloatingPoint.Type_,
  Integer._32,
  Integer._32.TextFormat,
  Integer.Type_,
  Sql,
  Sql.Database.PreparedStatement.Stream,
  Sql.Database.SystemInformation,
  Sql.Exception,
  Sql.Operator_.Binary,
  Sql.Schema.Information,
  Sql.Statement.DataManipulation,
  Sql.Statement.ResultSet.Select,
  Sql.Table,
  Sql.Table.Column.Reference,
  Sql.Table.Index.Column,
  Sql.Table.Physical,
  StructuredDocument.Node.Text,
  Text.Type_,
  Type_,
  Type_.System;

{ TSqlDatabase }

function TSqlDatabase.CreateTableDefinition(const SchemaName: TText; const TableName: TText): TObject;
var
  Table:                 TSqlPhysicalTable;
  InformationSchema:     TSqlInformationSchema;
  ColumnsTable:          TSqlColumnsTable;
  SqlResult:             TSqlResult;
  ColumnName:            TText;
  ColumnType:            TText;
  Type_:                 TType;
  KeyColumnUsageTable:   TSqlKeyColumnUsageTable;
  TableConstraintsTable: TSqlTableConstraintsTable;
  PrimaryKey:            array of TSqlTableIndexColumn;
  KeyColumn:             TSqlTableIndexColumn;
  i:                     TInteger32;
begin
  InformationSchema := (GetSystemInformation() as TSqlSystemInformation).GetInformationSchema();
  ColumnsTable      := InformationSchema.Columns;
  Table             := TSqlPhysicalTable.Create(TableName);

  SqlResult := Query(SelectGroupedOrderBy(
    [ ColumnsTable.ColumnName, ColumnsTable.DataType ],
    [ ColumnsTable ],
    [
      ColumnsTable.TableName = TableName,
      ColumnsTable.TableSchema = SchemaName
    ],
    [],
    [ ColumnsTable.OrdinalPosition ]
  ));

  while SqlResult.FetchRow() do
  begin
    ColumnName := SqlResult.ReadText();
    ColumnType := SqlResult.ReadText().ToLowerCase();

    if ColumnType = 'int' then
      Type_ := TBoundedIntegerType._32
    else if ColumnType = 'double' then
      Type_ := TFloatingPointType._64
    else if ColumnType = 'datetime' then
      Type_ := DDateTime
    else
      Type_ := TTextType.Long;

    Table.CreateColumn(ColumnName, TDocumentText.Create(ColumnName), Type_);
  end;

  SqlResult.Free();

  KeyColumnUsageTable   := InformationSchema.KeyColumnUsage;
  TableConstraintsTable := InformationSchema.TableConstraints;

  SqlResult := Query(SelectGroupedOrderBy(
    [ KeyColumnUsageTable.ColumnName ],
    [ KeyColumnUsageTable, TableConstraintsTable ],
    [
      TableConstraintsTable.TableSchema = SchemaName,
      TableConstraintsTable.TableName = TableName,
      TableConstraintsTable.ConstraintType = TableConstraintsTable.CONSTRAINT_PRIMARY_KEY,
      KeyColumnUsageTable.ConstraintName = TableConstraintsTable.ConstraintName,
      KeyColumnUsageTable.TableSchema = SchemaName,
      KeyColumnUsageTable.TableName = TableName
    ],
    [],
    [ KeyColumnUsageTable.OrdinalPosition ]
  ));

  SetLength(PrimaryKey, SqlResult.GetRowCount());

  for i := 0 to High(PrimaryKey) do
  begin
    SqlResult.FetchRow();
    ColumnName := SqlResult.ReadText();

    KeyColumn := TSqlTableIndexColumn.Create();
    KeyColumn.Column := Table.Columns.Find(TSqlTableColumn.THasIdentifier.Create(ColumnName));

    PrimaryKey[i] := KeyColumn;
  end;

  if System.Length(PrimaryKey) > 0 then
    Table.SetPrimaryKey(PrimaryKey);

  SqlResult.Free();
  Result := Table;
end;

function TSqlDatabase.Embellish(): TSqlDatabase;
begin
  Result := Self;
end;

procedure TSqlDatabase.Execute(Statement: TSqlStatement);
begin
  Query(Statement).Free();
end;

function TSqlDatabase.Exists(Statement: TSqlResultSetStatement): TBoolean;
begin
  Result := SelectBoolean(Select([Sql.Exists(Statement)], [], []));
end;

procedure TSqlDatabase.Flush();
begin
end;

function TSqlDatabase.Insert(Statement: TSqlStatement): TInteger;
begin
  Query(Statement);
  Result := InsertId;
end;

function TSqlDatabase.QuerySingleRow(Statement: TSqlStatement): TSqlResult;
begin
  Result := Query(Statement);

  if Result.GetRowCount() = 1 then
    Result.FetchRow()
  else
    raise ESql.Create('Exactly one row expected but found: ' + Integer32ToText(Result.GetRowCount()));
end;

function TSqlDatabase.SelectBoolean(Statement: TSqlResultSetStatement): TBoolean;
var
  SqlResult: TSqlResult;
begin
  SqlResult := Query(Statement);
  SqlResult.FetchRow();

  Result := SqlResult.ReadBoolean();
  SqlResult.Free();
end;

function TSqlDatabase.SelectBooleanWithDefault(Statement: TSqlResultSetStatement; DefaultValue: TBoolean): TBoolean;
var
  SqlResult: TSqlResult;
begin
  SqlResult := Query(Statement);

  if SqlResult.FetchRow() then
    Result := SqlResult.ReadBoolean()
  else
    Result := DefaultValue;

  SqlResult.Free();
end;

function TSqlDatabase.SelectColor(Statement: TSqlResultSetStatement): TRgbColor;
var
  SqlResult: TSqlResult;
begin
  SqlResult := Query(Statement);
  SqlResult.FetchRow();
  
  Result := SqlResult.ReadColor();
  SqlResult.Free();
end;

function TSqlDatabase.SelectColorWithDefault(Statement: TSqlResultSetStatement; const DefaultValue: TRgbColor): TRgbColor;
var
  SqlResult: TSqlResult;
begin
  SqlResult := Query(Statement);

  if SqlResult.FetchRow() then
    Result := SqlResult.ReadColor()
  else
    Result := DefaultValue;

  SqlResult.Free();
end;

function TSqlDatabase.SelectDate(Statement: TSqlResultSetStatement): TGregorianDate;
var
  SqlResult: TSqlResult;
begin
  SqlResult := Query(Statement);
  SqlResult.FetchRow();

  Result := SqlResult.ReadDate();
  SqlResult.Free();
end;

function TSqlDatabase.SelectDecimal(Statement: TSqlResultSetStatement): TDecimal;
var
  SqlResult: TSqlResult;
begin
  SqlResult := Query(Statement);
  SqlResult.FetchRow();

  Result := SqlResult.ReadDecimal();
  SqlResult.Free();
end;

function TSqlDatabase.SelectDecimalWithDefault(Statement: TSqlResultSetStatement; const DefaultValue: TDecimal): TDecimal;
var
  SqlResult: TSqlResult;
begin
  SqlResult := Query(Statement);

  if SqlResult.FetchRow() then
    Result := SqlResult.ReadDecimal
  else
    Result := DefaultValue;

  SqlResult.Free();
end;

function TSqlDatabase.SelectFloatingPoint(Statement: TSqlResultSetStatement): TFloatingPoint64;
var
  SqlResult: TSqlResult;
begin
  SqlResult := Query(Statement);
  SqlResult.FetchRow();

  Result := SqlResult.ReadFloatingPoint();
  SqlResult.Free();
end;

function TSqlDatabase.SelectFloatingPointWithDefault(Statement: TSqlResultSetStatement; DefaultValue: TFloatingPoint64): TFloatingPoint64;
var
  SqlResult: TSqlResult;
begin
  SqlResult := Query(Statement);

  if SqlResult.FetchRow() then
    Result := SqlResult.ReadFloatingPoint()
  else
    Result := DefaultValue;

  SqlResult.Free();
end;

function TSqlDatabase.SelectInstant(Statement: TSqlResultSetStatement): TGregorianInstant;
var
  SqlResult: TSqlResult;
begin
  SqlResult := Query(Statement);
  SqlResult.FetchRow();

  Result := SqlResult.ReadInstant();
  Result.AddReference();

  SqlResult.Free();
  Result.DiscardReference();
end;

function TSqlDatabase.SelectInteger(Statement: TSqlResultSetStatement): TInteger;
var
  SqlResult: TSqlResult;
begin
  SqlResult := Query(Statement);
  SqlResult.FetchRow();

  Result := SqlResult.ReadInteger();
  SqlResult.Free();
end;

function TSqlDatabase.SelectIntegerWithDefault(Statement: TSqlResultSetStatement): TInteger;
begin
  Result := SelectIntegerWithDefault(Statement, 0);
end;

function TSqlDatabase.SelectIntegerWithDefault(Statement: TSqlResultSetStatement; const DefaultValue: TInteger): TInteger;
var
  SqlResult: TSqlResult;
begin
  SqlResult := Query(Statement);

  if SqlResult.FetchRow() then
    Result := SqlResult.ReadInteger()
  else
    Result := DefaultValue;

  SqlResult.Free();
end;

function TSqlDatabase.SelectOrInsert(Table: TObject; const Columns: array of TSqlTableColumn; Row: TSqlRow): TInteger;
var
  SqlResult:    TSqlResult;
  Select:       TSqlSelect;
  InsertValues: TSqlInsertValues;
  Index:        TInteger32;
  CastTable:    TSqlTable;
begin
  CastTable := Table as TSqlTable; // TODO: This type cast should not be necessary when we Table is declared as a proper TSqlTable
  Row.AddReference();

  try
    if CastTable.PrimaryKey.Columns.Count = 1 then
    begin
      if System.Length(Columns) = Row.Columns.Count then
      begin
        Select := TSqlSelect.Create();
        Select.From.Add(CastTable.ToExpression());
        Select.Columns.AddTableColumn(CastTable.PrimaryKey.Columns.First.Column);

        for Index := 0 to High(Columns) do
          Select.Restrictions.Add(TSqlEqual.Create(TSqlTableColumnReference.Create(Columns[Index]), Row.Columns[Index]));

        SqlResult := Query(Select);

        if SqlResult.FetchRow() then
          Result := SqlResult.ReadInteger()
        else
        begin
          InsertValues := TSqlInsertValues.Create(CastTable);
          InsertValues.Columns.AddAll(Columns);
          InsertValues.Rows.Add(Row);

          Result := Insert(InsertValues);
        end;

        SqlResult.Free();
      end
      else
        raise ESql.Create('Mismatch between columns and values');
    end
    else
      raise ESql.Create('Primary key with one integer column expected');
  finally
    Row.ReleaseReference();
  end;
end;

function TSqlDatabase.SelectStream(Statement: TSqlStatement): TInputStream;
var
  PreparedStatement: TSqlPreparedStatement;
  StatementResult:   TSqlResult;
  Stream:            TSqlPreparedStatementInputStream;
  Block:             TByteBlock;
begin
  PreparedStatement := Prepare(Statement);

  StatementResult := PreparedStatement.Execute();
  StatementResult.FetchRow();

  Block := StatementResult.ReadByteBlock();

  if Block <> nil then
  begin
    Stream := TSqlPreparedStatementInputStream.Create(Block.CreateInputStream());
    Stream.Statement       := PreparedStatement;
    Stream.StatementResult := StatementResult;
    Stream.Block           := Block;

    Result := Stream;
  end
  else
  begin
    Result := nil;

    StatementResult.Free();
    PreparedStatement.Free();
  end;
end;

function TSqlDatabase.SelectText(Statement: TSqlResultSetStatement): TText;
var
  SqlResult: TSqlResult;
begin
  SqlResult := Query(Statement);
  SqlResult.FetchRow();
  
  Result := SqlResult.ReadText();
  SqlResult.Free();
end;

function TSqlDatabase.SelectTextWithDefault(Statement: TSqlResultSetStatement): TText;
begin
  Result := SelectTextWithDefault(Statement, '');
end;

function TSqlDatabase.SelectTextWithDefault(Statement: TSqlResultSetStatement; const DefaultValue: TText): TText;
var
  SqlResult: TSqlResult;
begin
  SqlResult := Query(Statement);

  if SqlResult.FetchRow() then
    Result := SqlResult.ReadText()
  else
    Result := DefaultValue;

  SqlResult.Free();
end;

function TSqlDatabase.SelectUuid(Statement: TSqlResultSetStatement): TUuid;
var
  SqlResult: TSqlResult;
begin
  SqlResult := Query(Statement);
  SqlResult.FetchRow();

  Result := SqlResult.ReadUuid();
  SqlResult.Free();
end;

function TSqlDatabase.SelectUuidWithDefault(Statement: TSqlResultSetStatement; const DefaultValue: TUuid): TUuid;
var
  SqlResult: TSqlResult;
begin
  SqlResult := Query(Statement);

  if SqlResult.FetchRow() then
    Result := SqlResult.ReadUuid()
  else
    Result := DefaultValue;

  SqlResult.Free();
end;

function TSqlDatabase.TableExists(const Name: TText): TBoolean;
var
  TablesTable: TSqlTablesTable;
begin
  TablesTable := (GetSystemInformation() as TSqlSystemInformation).GetInformationSchema().Tables;
  Result      := Exists(Select([1], [TablesTable], [TablesTable.TableSchema = ConnectionSettings.DatabaseName, TablesTable.TableName = Name]));
end;

function TSqlDatabase.TableHasConstraint(const Table: TText; const Constraint: TText): TBoolean;
var
  ConstraintsTable: TSqlTableConstraintsTable;
begin
  ConstraintsTable := (GetSystemInformation() as TSqlSystemInformation).GetInformationSchema().TableConstraints;

  Result := Exists(
    Select(
      [ 1 ],
      [ ConstraintsTable ],
      [
        ConstraintsTable.TableSchema = ConnectionSettings.DatabaseName,
        ConstraintsTable.TableName = Table,
        ConstraintsTable.ConstraintName = Constraint
      ]
    )
  );
end;

end.