Microsoft Fabric Reference

Reference material for Microsoft Fabric Publishing -- data type mappings, querying, troubleshooting, and CLI arguments.

Data Type Mapping

Source types map automatically to Fabric-compatible Delta Lake types. LakeXpress exports through Parquet, so the mapping is driven by the normalized source type name.

Pick your source database:

PostgreSQL

PostgreSQL to Fabric

PostgreSQL Type	Fabric Type
SMALLINT	SMALLINT
INTEGER, INT4	INT
BIGINT, INT8	BIGINT
NUMERIC(p,s)	DECIMAL(p,s)
REAL, FLOAT4	REAL
DOUBLE PRECISION, FLOAT8	FLOAT
VARCHAR(n)	VARCHAR(n)
TEXT	VARCHAR(MAX)
CHAR(n)	CHAR(n)
BOOLEAN	BIT
DATE	DATE
TIME	TIME
TIMESTAMP	DATETIME2
TIMESTAMPTZ	DATETIMEOFFSET
BYTEA	VARBINARY(MAX)
UUID	UNIQUEIDENTIFIER
JSON, JSONB, array []	NVARCHAR(MAX)

SQL Server

SQL Server to Fabric

SQL Server Type	Fabric Type
TINYINT	TINYINT
SMALLINT	SMALLINT
INT	INT
BIGINT	BIGINT
DECIMAL(p,s)	DECIMAL(p,s)
MONEY	DECIMAL(19,4)
SMALLMONEY	DECIMAL(10,4)
FLOAT	FLOAT
REAL	REAL
BIT	BIT
VARCHAR(n)	VARCHAR(n)
NVARCHAR(n)	NVARCHAR(n)
CHAR(n)	CHAR(n)
NCHAR(n)	NCHAR(n)
TEXT	VARCHAR(MAX)
NTEXT	NVARCHAR(MAX)
DATE	DATE
DATETIME, DATETIME2, SMALLDATETIME	DATETIME2
DATETIMEOFFSET	DATETIMEOFFSET
VARBINARY	VARBINARY(MAX)
UNIQUEIDENTIFIER	UNIQUEIDENTIFIER

Oracle

Oracle to Fabric

Oracle Type	Fabric Type
NUMBER	DECIMAL(38,18)
NUMBER(p,s)	DECIMAL(p,s)
FLOAT	FLOAT
VARCHAR2(n)	VARCHAR(n)
NVARCHAR2(n)	NVARCHAR(n)
CHAR(n)	CHAR(n)
CLOB	VARCHAR(MAX)
NCLOB	NVARCHAR(MAX)
DATE	DATE
TIMESTAMP	DATETIME2
RAW, BLOB	VARBINARY(MAX)

Teradata

Teradata to Fabric

Teradata Type	Fabric Type
BYTEINT, VARBYTE	NVARCHAR(MAX)
SMALLINT	SMALLINT
INTEGER	INT
BIGINT	BIGINT
DECIMAL(p,s), NUMERIC(p,s)	DECIMAL(p,s)
NUMBER	DECIMAL(38,18)
FLOAT, REAL	FLOAT
VARCHAR(n)	VARCHAR(n)
CHAR(n)	CHAR(n)
CLOB	VARCHAR(MAX)
DATE	DATE
TIME	TIME
TIMESTAMP	DATETIME2
BYTE, BLOB	VARBINARY(MAX)

MySQL

MySQL to Fabric

MySQL Type	Fabric Type
TINYINT	TINYINT
SMALLINT	SMALLINT
MEDIUMINT, YEAR, TINYTEXT, MEDIUMTEXT, LONGTEXT, ENUM, SET, TINYBLOB, MEDIUMBLOB, LONGBLOB, JSON	NVARCHAR(MAX)
INT	INT
BIGINT	BIGINT
DECIMAL(p,s)	DECIMAL(p,s)
FLOAT, DOUBLE	FLOAT
BIT	BIT
VARCHAR(n)	VARCHAR(n)
CHAR(n)	CHAR(n)
TEXT	VARCHAR(MAX)
DATE	DATE
TIME	TIME
DATETIME, TIMESTAMP	DATETIME2
BINARY, VARBINARY, BLOB	VARBINARY(MAX)

MariaDB

MariaDB to Fabric

MariaDB Type	Fabric Type
TINYINT	TINYINT
SMALLINT	SMALLINT
MEDIUMINT, YEAR, TINYTEXT, MEDIUMTEXT, LONGTEXT, ENUM, SET, TINYBLOB, MEDIUMBLOB, LONGBLOB, JSON	NVARCHAR(MAX)
INT	INT
BIGINT	BIGINT
DECIMAL(p,s)	DECIMAL(p,s)
FLOAT, DOUBLE	FLOAT
BIT	BIT
VARCHAR(n)	VARCHAR(n)
CHAR(n)	CHAR(n)
TEXT	VARCHAR(MAX)
DATE	DATE
TIME	TIME
DATETIME, TIMESTAMP	DATETIME2
BINARY, VARBINARY, BLOB	VARBINARY(MAX)

SAP HANA

SAP HANA to Fabric

SAP HANA Type	Fabric Type
TINYINT	TINYINT
SMALLINT	SMALLINT
INTEGER	INT
BIGINT	BIGINT
DECIMAL(p,s)	DECIMAL(p,s)
SMALLDECIMAL, NCLOB, SECONDDATE	NVARCHAR(MAX)
REAL	REAL
DOUBLE	FLOAT
BOOLEAN	BIT
VARCHAR(n)	VARCHAR(n)
NVARCHAR(n)	NVARCHAR(n)
CHAR(n)	CHAR(n)
NCHAR(n)	NCHAR(n)
CLOB, TEXT	VARCHAR(MAX)
DATE	DATE
TIME	TIME
TIMESTAMP	DATETIME2
VARBINARY, BLOB	VARBINARY(MAX)

Querying Tables

SQL Analytics Endpoint

-- Query a Delta table
SELECT * FROM your_lakehouse.dbo.customer LIMIT 10;

-- Aggregation
SELECT
    c_nationkey,
    COUNT(*) as customer_count,
    SUM(c_acctbal) as total_balance
FROM your_lakehouse.dbo.customer
GROUP BY c_nationkey
ORDER BY customer_count DESC;

Spark Notebooks

# Read a Delta table
df = spark.read.table("customer")
df.show(10)

# Query with SQL
spark.sql("""
    SELECT c_nationkey, COUNT(*) as cnt
    FROM customer
    GROUP BY c_nationkey
""").show()

# Write results back
result_df.write.mode("overwrite").saveAsTable("customer_summary")

Troubleshooting

Common Issues

Authentication Errors

Error: AADSTS7000215: Invalid client secret provided

Regenerate your client secret in Azure AD and update credentials.json.

Error: The user or service principal does not have access to the workspace

1. Verify the Service Principal is added to the workspace
2. Ensure it has Member or Contributor role
3. Wait a few minutes for permissions to propagate

OneLake Connection Issues

Error: Unable to connect to OneLake storage

1. Verify the directory format: onelake://workspace-name/lakehouse-name/
2. Check that the Service Principal has Storage Blob Data Contributor role
3. Ensure workspace and lakehouse names are correct (case-sensitive)

Table Creation Failures

Error: Failed to create table in Lakehouse

1. Verify the SQL analytics endpoint is correct
2. Check that the Lakehouse is active (not paused)
3. Ensure sufficient capacity units are available
4. Confirm Parquet files were exported to OneLake

SQL Endpoint Connection Issues

Error: Cannot connect to SQL analytics endpoint

1. Verify the SQL endpoint hostname
2. Ensure the SQL analytics endpoint is enabled
3. Check firewall rules if connecting from on-premises

Verifying Export Success

Check files in OneLake:

1. Open your Lakehouse in Fabric portal
2. Go to the Files section
3. Verify Parquet files exist in the expected folders

Check tables:

1. Open the SQL analytics endpoint
2. Expand Tables in the object explorer
3. Verify your tables appear

Debug Mode

./LakeXpress sync \
    -a credentials.json \
    --lxdb_auth_id lxdb_postgres \
    --sync_id <SYNC_ID> \
    --log_level DEBUG

CLI Reference

Fabric Publishing Arguments

Option	Type	Description
--publish_target ID	String	Credential ID for Fabric publishing (required)
--publish_method METHOD	Enum	internal (Delta tables, recommended) or external (SQL views) (default: external)
--publish_table_pattern PATTERN	String	Table naming pattern for the Lakehouse's flat namespace (default: {table}; include {schema}, e.g. {schema}_{table}, when exporting several schemas)
--n_jobs N	Integer	Parallel workers for table creation (default: 1)

Full Example

See Examples & Recipes: Microsoft Fabric for complete, ready-to-run commands.

See Also

• Microsoft Fabric Publishing - Setup and usage guide
• Intermediate Storage - OneLake configuration
• CLI Reference - All command-line options