SQL Schema construction

DbSeeder/Program.cs

@@ -11,18 +11,18 @@
     {
         const string sqlScript =
             """
-            CREATE TABLE users
+            CREATE TABLE profiles
             (
                 id         INT AUTO_INCREMENT PRIMARY KEY,
-                name       VARCHAR(122) NOT NULL UNIQUE,
-                profile_id INT,
-                FOREIGN KEY (profile_id) REFERENCES profiles(id)
+                nickname   VARCHAR(122) NOT NULL UNIQUE
             );
 
-            CREATE TABLE profiles
+            CREATE TABLE users
             (
                 id         INT AUTO_INCREMENT PRIMARY KEY,
-                nickname   VARCHAR(122) NOT NULL UNIQUE
+                name       VARCHAR(122) NOT NULL UNIQUE,
+                profile_id INT,
+                FOREIGN KEY (profile_id) REFERENCES profiles(id)
             );
             """;
         var lexer = new SqlLexer(sqlScript);
@@ -56,7 +56,7 @@
 
     private static void PrintSyntaxTree(SyntaxTreeNode? node, string indent = "")
     {
         Console.WriteLine($"{indent}{node.Value} --> ({node.Type})");
         foreach (var child in node.Children)
         {
             PrintSyntaxTree(child, indent + "  ");

DbSeeder/Schema/Column.cs

@@ -1,9 +1,46 @@
 namespace DbSeeder.Schema;
 
-public class Column(string name, string dataType, string dataTypeConstraint, string[] constraints)
+public record Column
 {
-    public string Name { get; } = name;
-    public string DataType { get; } = dataType;
-    public string DataTypeConstraint { get; set; } = dataTypeConstraint;
-    public string[] Constraints { get; set; } = constraints;
+    public Column(string name,
+        string dataType,
+        string dataTypeConstraint,
+        string[] constraints)
+    {
+        Name = name;
+        DataType = dataType;
+        DataTypeConstraint = dataTypeConstraint;
+
+        constraints = constraints.Select(c => c.ToLower()).ToArray();
+        IsAutoIncrement = constraints.Contains("auto_increment", StringComparer.OrdinalIgnoreCase);
+        IsNotNull = constraints.Contains("not null", StringComparer.OrdinalIgnoreCase);
+        IsUnique = constraints.Contains("unique", StringComparer.OrdinalIgnoreCase);
+        IsPrimaryKey = constraints.Contains("primary key", StringComparer.OrdinalIgnoreCase);
+
+        var fkConstraint = constraints.FirstOrDefault(
+            c => c.StartsWith("foreign key", StringComparison.OrdinalIgnoreCase));
+        IsForeignKey = fkConstraint is not null;
+
+        if (IsForeignKey)
+        {
+            var refTableAndCol = fkConstraint![12..].Split("|");
+
+            var refTableName = refTableAndCol[0];
+            var refColumnName = refTableAndCol[1];
+
+            ForeignKeyRef = new ForeignKeyRef(refTableName, refColumnName);
+        }
+    }
+
+    public string Name { get; }
+    public string DataType { get; }
+    public string DataTypeConstraint { get; }
+
+    public bool IsAutoIncrement { get; }
+    public bool IsPrimaryKey { get; }
+    public bool IsForeignKey { get; }
+    public bool IsNotNull { get; }
+    public bool IsUnique { get; }
+
+    public ForeignKeyRef? ForeignKeyRef { get; }
 }

DbSeeder/Schema/ForeignKey.cs

@@ -0,0 +1,7 @@
+namespace DbSeeder.Schema;
+
+public record ForeignKey(
+    Table Table,
+    Column Column,
+    Table RefTable,
+    Column RefColumn);

DbSeeder/Schema/ForeignKeyRef.cs

@@ -0,0 +1,5 @@
+namespace DbSeeder.Schema;
+
+public record ForeignKeyRef(
+    string TableName,
+    string ColumnName);

DbSeeder/Schema/PrimaryKey.cs

@@ -0,0 +1,5 @@
+namespace DbSeeder.Schema;
+
+public record PrimaryKey(
+    Table Table,
+    Column Column);

DbSeeder/Schema/SqlSchema.cs

@@ -3,10 +3,12 @@
 public class SqlSchema
 {
     private readonly List<Table> _tables = [];
+
     public IReadOnlyList<Table> Tables => _tables;
 
     public void AddTable(Table table)
-    {
-        _tables.Add(table);
-    }
+        => _tables.Add(table);
+
+    public Table? GetTableByName(string tableName)
+        => _tables.FirstOrDefault(t => t.Name.Equals(tableName, StringComparison.OrdinalIgnoreCase));
 }

DbSeeder/Schema/SqlSchemaBuilder.cs

@@ -13,7 +13,7 @@
         return _sqlSchema;
     }
 
     public void Visit(SyntaxTreeNode? rootNode)
     {
         ArgumentNullException.ThrowIfNull(rootNode);
 
@@ -42,10 +42,10 @@
 
     private void TraverseCreateStatement(SyntaxTreeNode createStatementNode)
     {
         var child = createStatementNode.Children.First();
         if (child!.Type is SyntaxTreeNodeType.CreateTable)
         {
             var tableRoot = child.Children.First();
             var table = CreateTable(tableRoot!);
             _sqlSchema!.AddTable(table);
         }
@@ -54,21 +54,19 @@
     private Table CreateTable(SyntaxTreeNode tableRoot)
     {
         var tableName = tableRoot.Value;
-        var table = new Table(tableName);
+        var table = new Table(tableName, _sqlSchema!);
 
         // Actually, now we expect that table root contains only cols, but in the future more sub-nodes can be added,
         // so we have to be sure that we're working exactly with a node that contains cols.
         var colsRoot = tableRoot.Children.First(x => x?.Type is SyntaxTreeNodeType.TableColumns);
         var cols = ParseColumns(colsRoot!);
-        table.Columns.AddRange(cols);
+        table.AddColumns(cols);
 
         return table;
     }
 
     private IEnumerable<Column> ParseColumns(SyntaxTreeNode colsRoot)
-    {
-        return colsRoot.Children.Select(GetColumn!).ToList();
-    }
+        => colsRoot.Children.Select(GetColumn!).ToList();
 
     private Column GetColumn(SyntaxTreeNode columnNode)
     {
@@ -97,7 +95,8 @@
                     constraints.Add(node.Value);
                     break;
                 case SyntaxTreeNodeType.ForeignKeyDefinition:
-                    // TODO: Implement processing FK constraint correctly
+                    var fkConstraint = $"foreign key {node.Children[1]?.Value}|{node.Children[2]?.Value}";
+                    constraints.Add(fkConstraint);
                     break;
             }
         }

DbSeeder/Schema/Table.cs

@@ -1,7 +1,74 @@
 namespace DbSeeder.Schema;
 
-public class Table(string name)
+public class Table(string name, SqlSchema schema)
 {
+    private readonly List<Column> _columns = [];
+    private readonly List<ForeignKey> _foreignKeys = [];
+
+    // There are some rules how to deal if PK is not defined
+    // ex: find the first attribute with NOT NULL & UNIQUE constraints
+    public PrimaryKey? PrimaryKey { get; private set; }
     public string Name { get; } = name;
-    public List<Column> Columns { get; } = [];
+    public IReadOnlyList<Column> Columns => _columns;
+    public IReadOnlyList<ForeignKey> ForeignKeys => _foreignKeys;
+
+    public void AddColumns(IEnumerable<Column> columns)
+    {
+        foreach (var column in columns)
+        {
+            AddColumn(column);
+        }
+    }
+
+    private void AddColumn(Column column)
+    {
+        ArgumentNullException.ThrowIfNull(column);
+        _columns.Add(column);
+
+        if (column.IsPrimaryKey)
+        {
+            SetTablePrimaryKey(column);
+        }
+        else if (column.IsForeignKey)
+        {
+            SetTableForeignKey(column);
+        }
+    }
+
+    private void SetTablePrimaryKey(Column column)
+    {
+        if (PrimaryKey != null)
+        {
+            throw new ArgumentException("Table can not contains more that one PRIMARY KEY");
+        }
+
+        PrimaryKey = new PrimaryKey(this, column);
+    }
+
+    private void SetTableForeignKey(Column column)
+    {
+        ArgumentNullException.ThrowIfNull(column.ForeignKeyRef);
+
+        var refTable = schema.GetTableByName(column.ForeignKeyRef.TableName);
+        if (refTable is null)
+        {
+            throw new InvalidOperationException($"Referenced table {column.ForeignKeyRef.TableName} is not exists " +
+                                                $"in current schema. Validate the order of the create statements, " +
+                                                $"it's matter");
+        }
+
+        var refColumn = refTable.GetColumnByName(column.ForeignKeyRef.ColumnName);
+        if (refColumn is null)
+        {
+            throw new InvalidOperationException($"Referenced table {column.ForeignKeyRef.TableName} is not exists " +
+                                                $"in current schema. Validate the order of the create statements, " +
+                                                $"it's matter");
+        }
+
+        var fk = new ForeignKey(this, column, refTable, refColumn);
+        _foreignKeys.Add(fk);
+    }
+
+    private Column? GetColumnByName(string columnName)
+        => Columns.FirstOrDefault(c => c.Name.Equals(columnName, StringComparison.Ordinal));
 }