WIP: Render database schema using Mermaid.js

Still need to:
* Move mermaid.js to static files
* Make template for mermaid wrapper
* Create new page for SQL viewer then add explorer

features/sql_viewer.py

@@ -0,0 +1,94 @@
+class SQLViewer:
+    def __init__(self, db_connection_method):
+        self.execute = db_connection_method
+
+    def get_schema_info(self, schema='public'):
+        # Get all table names in the specified schema
+        tables_result = self.execute("""
+            SELECT table_name
+            FROM information_schema.tables
+            WHERE table_schema = %s AND table_type = 'BASE TABLE';
+        """, [schema])
+        tables = [row['table_name'] for row in tables_result]
+
+        schema_info = {}
+
+        for table in tables:
+            # Get columns and data types
+            columns_result = self.execute("""
+                SELECT column_name, data_type
+                FROM information_schema.columns
+                WHERE table_schema = %s AND table_name = %s;
+            """, [schema, table])
+            columns = [(row['column_name'], row['data_type']) for row in columns_result]
+
+            # Get foreign keys
+            foreign_keys_result = self.execute("""
+                SELECT
+                    kcu.column_name AS fk_column,
+                    ccu.table_name AS referenced_table,
+                    ccu.column_name AS referenced_column
+                FROM
+                    information_schema.table_constraints AS tc
+                    JOIN information_schema.key_column_usage AS kcu
+                    ON tc.constraint_name = kcu.constraint_name
+                    AND tc.table_schema = kcu.table_schema
+                    JOIN information_schema.constraint_column_usage AS ccu
+                    ON ccu.constraint_name = tc.constraint_name
+                    AND ccu.table_schema = tc.table_schema
+                WHERE
+                    tc.constraint_type = 'FOREIGN KEY' AND
+                    tc.table_schema = %s AND
+                    tc.table_name = %s;
+            """, [schema, table])
+            foreign_keys = [
+                (row['fk_column'], row['referenced_table'], row['referenced_column'])
+                for row in foreign_keys_result
+            ]
+
+            schema_info[table] = {
+                'columns': columns,
+                'foreign_keys': foreign_keys
+            }
+
+        return schema_info
+    
+    def map_data_type(self, postgres_type):
+        type_mapping = {
+            'integer': 'int',
+            'bigint': 'int',
+            'smallint': 'int',
+            'character varying': 'string',
+            'varchar': 'string',
+            'text': 'string',
+            'date': 'date',
+            'timestamp without time zone': 'datetime',
+            'timestamp with time zone': 'datetime',
+            'boolean': 'bool',
+            'numeric': 'float',
+            'real': 'float'
+            # Add more mappings as needed
+        }
+        return type_mapping.get(postgres_type, 'string')  # Default to 'string' if type not mapped
+
+    def generate_mermaid_er(self, schema_info):
+        mermaid_lines = ["erDiagram"]
+        
+        for table, info in schema_info.items():
+            # Define the table and its columns
+            mermaid_lines.append(f"    {table} {{")
+            for column_name, data_type in info['columns']:
+                # Convert PostgreSQL data types to Mermaid-compatible types
+                mermaid_data_type = self.map_data_type(data_type)
+                mermaid_lines.append(f"        {mermaid_data_type} {column_name}")
+            mermaid_lines.append("    }")
+        
+        # Define relationships
+        for table, info in schema_info.items():
+            for fk_column, referenced_table, referenced_column in info['foreign_keys']:
+                # Mermaid relationship syntax: [Table1] }|--|| [Table2] : "FK_name"
+                relation = f"    {table} }}|--|| {referenced_table} : \"{fk_column} to {referenced_column}\""
+                mermaid_lines.append(relation)
+        
+        return "\n".join(mermaid_lines)
+