Database Configuration Source

The database configuration source supports reading and writing configuration from relational databases, suitable for scenarios requiring centralized configuration management.

Installation

dotnet add package Apq.Cfg.Database

Default Level

The default level for this configuration source is CfgSourceLevels.Database (100).

If you don't specify the level parameter, the default level will be used:

// Uses default level 100
.AddDatabase(options => { ... })

// Specify custom level
.AddDatabase(options => { ... }, level: 150)

Supported Databases

Database	Provider Value
Microsoft SQL Server	SqlServer
MySQL	MySql
PostgreSQL	PostgreSQL or Postgres
Oracle	Oracle
SQLite	SQLite

Basic Usage

using Apq.Cfg;
using Apq.Cfg.Database;

var cfg = new CfgBuilder()
    .AddDatabase(options =>
    {
        options.Provider = "SqlServer";
        options.ConnectionString = "Server=localhost;Database=ConfigDb;Trusted_Connection=True;";
        options.Table = "AppConfig";
        options.KeyColumn = "ConfigKey";
        options.ValueColumn = "ConfigValue";
    })  // Uses default level 100
    .Build();

// Read configuration
var connStr = cfg["Database:ConnectionString"];
var timeout = cfg.GetValue<int>("Database:Timeout");

Method Signature

public static CfgBuilder AddDatabase(
    this CfgBuilder builder,
    Action<DatabaseOptions> configure,
    int? level = null,
    bool isPrimaryWriter = false)

Configuration Options

Full Configuration

var cfg = new CfgBuilder()
    .AddDatabase(options =>
    {
        options.Provider = "SqlServer";
        options.ConnectionString = "Server=localhost;Database=ConfigDb;...";
        options.Table = "AppConfig";
        options.KeyColumn = "ConfigKey";
        options.ValueColumn = "ConfigValue";
        options.CommandTimeoutMs = 5000;
    }, isPrimaryWriter: true)  // Uses default level 100
    .Build();

Options Description

Option	Type	Default	Description
Provider	string?	null	Database provider name
ConnectionString	string?	null	Database connection string
Table	string?	null	Configuration table name
KeyColumn	string?	null	Key column name
ValueColumn	string?	null	Value column name
CommandTimeoutMs	int	5000	Command timeout (milliseconds)

Table Structure

SQL Server

CREATE TABLE AppConfig (
    ConfigKey NVARCHAR(256) PRIMARY KEY,
    ConfigValue NVARCHAR(MAX)
);

MySQL

CREATE TABLE app_config (
    config_key VARCHAR(256) PRIMARY KEY,
    config_value TEXT
);

PostgreSQL

CREATE TABLE app_config (
    config_key VARCHAR(256) PRIMARY KEY,
    config_value TEXT
);

SQLite

CREATE TABLE Config (
    Key TEXT PRIMARY KEY,
    Value TEXT
);

Database Examples

SQL Server

var cfg = new CfgBuilder()
    .AddDatabase(options =>
    {
        options.Provider = "SqlServer";
        options.ConnectionString = "Server=.;Database=MyDb;Trusted_Connection=True;";
        options.Table = "AppConfig";
        options.KeyColumn = "Key";
        options.ValueColumn = "Value";
    })  // Uses default level 100
    .Build();

MySQL

var cfg = new CfgBuilder()
    .AddDatabase(options =>
    {
        options.Provider = "MySql";
        options.ConnectionString = "Server=localhost;Database=mydb;User=root;Password=...;";
        options.Table = "app_config";
        options.KeyColumn = "config_key";
        options.ValueColumn = "config_value";
    })  // Uses default level 100
    .Build();

PostgreSQL

var cfg = new CfgBuilder()
    .AddDatabase(options =>
    {
        options.Provider = "PostgreSQL";
        options.ConnectionString = "Host=localhost;Database=mydb;Username=postgres;Password=...;";
        options.Table = "app_config";
        options.KeyColumn = "config_key";
        options.ValueColumn = "config_value";
    })  // Uses default level 100
    .Build();

Oracle

var cfg = new CfgBuilder()
    .AddDatabase(options =>
    {
        options.Provider = "Oracle";
        options.ConnectionString = "Data Source=localhost:1521/ORCL;User Id=user;Password=...;";
        options.Table = "APP_CONFIG";
        options.KeyColumn = "CONFIG_KEY";
        options.ValueColumn = "CONFIG_VALUE";
    })  // Uses default level 100
    .Build();

SQLite

var cfg = new CfgBuilder()
    .AddDatabase(options =>
    {
        options.Provider = "SQLite";
        options.ConnectionString = "Data Source=config.db";
        options.Table = "Config";
        options.KeyColumn = "Key";
        options.ValueColumn = "Value";
    })  // Uses default level 100
    .Build();

Writable Configuration

The database configuration source supports writing configuration:

var cfg = new CfgBuilder()
    .AddDatabase(options =>
    {
        options.Provider = "SqlServer";
        options.ConnectionString = "Server=localhost;Database=ConfigDb;...";
        options.Table = "AppConfig";
        options.KeyColumn = "ConfigKey";
        options.ValueColumn = "ConfigValue";
    }, isPrimaryWriter: true)  // Uses default level 100
    .Build();

// Write configuration
cfg["App:Version"] = "2.0.0";
await cfg.SaveAsync();

Mixed with Local Configuration

var cfg = new CfgBuilder()
    // Local base configuration (uses default level 0)
    .AddJsonFile("config.json")
    // Database configuration (uses default level 100)
    .AddDatabase(options =>
    {
        options.Provider = "SqlServer";
        options.ConnectionString = "Server=localhost;Database=ConfigDb;...";
        options.Table = "AppConfig";
        options.KeyColumn = "ConfigKey";
        options.ValueColumn = "ConfigValue";
    }, isPrimaryWriter: true)
    // Environment variables (uses default level 400)
    .AddEnvironmentVariables(prefix: "APP_")
    .Build();

Initialize Data

You can use SQL scripts to initialize configuration data:

-- SQL Server
INSERT INTO AppConfig (ConfigKey, ConfigValue) VALUES
('Database:Host', 'localhost'),
('Database:Port', '5432'),
('Database:Name', 'mydb'),
('App:Name', 'MyApplication'),
('App:Version', '1.0.0');

Next Steps

• Redis Configuration Source - Redis key-value storage
• Consul Configuration Source - HashiCorp Consul