relspecgo/pkg/writers/mssql/README.md

MSSQL Writer

Generates Microsoft SQL Server DDL (Data Definition Language) from database schema models.

Features

• DDL Generation: Generates complete SQL scripts for creating MSSQL schema
• Schema Support: Creates multiple schemas with proper naming
• Bracket Notation: Uses [schema].[table] bracket notation for identifiers
• Identity Columns: Generates IDENTITY(1,1) for auto-increment columns
• Constraints: Generates primary keys, foreign keys, unique, and check constraints
• Indexes: Creates indexes with unique support
• Extended Properties: Uses sp_addextendedproperty for comments
• Direct Execution: Can directly execute DDL on MSSQL database
• Schema Flattening: Optional schema flattening for compatibility

Features by Phase

1. Phase 1: Create schemas
2. Phase 2: Create tables with columns, identity, and defaults
3. Phase 3: Add primary key constraints
4. Phase 4: Create indexes
5. Phase 5: Add unique constraints
6. Phase 6: Add check constraints
7. Phase 7: Add foreign key constraints
8. Phase 8: Add extended properties (comments)

Type Mappings

Canonical Type	MSSQL Type
int	INT
int64	BIGINT
int16	SMALLINT
int8	TINYINT
bool	BIT
float32	REAL
float64	FLOAT
decimal	NUMERIC
string	NVARCHAR(255)
text	NVARCHAR(MAX)
timestamp	DATETIME2
timestamptz	DATETIMEOFFSET
uuid	UNIQUEIDENTIFIER
bytea	VARBINARY(MAX)
date	DATE
time	TIME

Usage

Generate SQL File

import "git.warky.dev/wdevs/relspecgo/pkg/writers/mssql"
import "git.warky.dev/wdevs/relspecgo/pkg/writers"

writer := mssql.NewWriter(&writers.WriterOptions{
    OutputPath: "schema.sql",
    FlattenSchema: false,
})

err := writer.WriteDatabase(db)
if err != nil {
    panic(err)
}

Direct Database Execution

writer := mssql.NewWriter(&writers.WriterOptions{
    OutputPath: "",
    Metadata: map[string]interface{}{
        "connection_string": "sqlserver://sa:password@localhost/newdb",
    },
})

err := writer.WriteDatabase(db)
if err != nil {
    panic(err)
}

CLI Usage

Generate SQL file:

relspec convert --from json --from-path schema.json \
                --to mssql --to-path schema.sql

Execute directly to database:

relspec convert --from json --from-path schema.json \
                --to mssql \
                --metadata '{"connection_string":"sqlserver://sa:password@localhost/mydb"}'

Default Values

The writer supports several default value patterns:

• Functions: GETDATE(), CURRENT_TIMESTAMP()
• Literals: strings wrapped in quotes, numbers, booleans (0/1 for BIT)
• CAST expressions

Comments/Extended Properties

Table and column descriptions are stored as MS_Description extended properties:

EXEC sp_addextendedproperty
  @name = 'MS_Description',
  @value = 'Table description here',
  @level0type = 'SCHEMA', @level0name = 'dbo',
  @level1type = 'TABLE', @level1name = 'my_table';

Testing

Run tests with:

go test ./pkg/writers/mssql/...

Limitations

• Views are not currently supported in the writer
• Sequences are not supported (MSSQL uses IDENTITY instead)
• Partitioning and advanced features are not supported
• Generated DDL assumes no triggers or computed columns